Project no. 003956 Project acronym NOMIRACLE Project title Novel Methods for Integrated Risk Assessment of Cumulative Stressors in Europe Instrument IP Thematic Priority 1.1.6.3, ‘Global Change and Ecosystems’ Topic VII.1.1.a, ‘Development of risk assessment methodologies’ Deliverable reference number and title: D.2.2.16 Report on the evaluation of new extraction materials and analytical techniques for polar organic compounds such as pesticides and pharmaceutical residues in soils and waste water Due date of deliverable: 1 November 2009 Start date of project: 1 November 2004 Actual submission date: 14 September 2009 Duration: 5 years Organisation name of lead contractor for this deliverable: CSICRevision [draft, 1, 2, …]: Project co-funded by the European Commission within the Sixth Framework Programme (2002-2006) Dissemination Level PU PP RE CO Public Restricted to other programme participants (including the Commission Services) Restricted to a group specified by the consortium (including the Commission Services) Confidential, only for members of the consortium (including the Commission Services) X 1 Authors and their organisation: María J. García Galán, CSIC M. Silvia Díaz-Cruz, CSIC Damià Barceló, CSIC Thomas Alsberg, ITM J. Magner, ITM Deliverable no: D.2.2.16 Nature: R Status: Draft 1 Dissemination level: PU Date of delivery: Date of publishing: Reviewed by (name and period): 2 TABLE OF CONTENTS Summary 1. General remarks 2. Extraction and purification of environmental samples. 2.1. Sulfonamides in natural water samples 2.1.1 Offline SPE 2.1.2 Online SPE 2.2. Triazines and triazine metabolites in soils and natural waters 2.3. Polar organic compounds in waste waters 3. RESULTS 3.1. Sulfonamides 3.1.1. Offline SPE-LC-QqLIT-MS 3.1.2. Online SPE-LC-QqLIT-MS 3.2. Triazines 3.3. Polar organic contaminants Conclusions References Annex A Annex B Annex C 3 D.2.2.16 Report on the evaluation of a new extraction material and different analytical techniques for polar compounds such as pesticides and pharmaceutical residues in soils and environmental waters. SUMMARY This report gathers various parallel studies carried out in Sweden and Spain for the determination of polar contaminants such as pharmaceutical residues and pesticides in different water matrices and soil (only for pesticides). In first place, two new analytical methods based on liquid chromatography–quadrupole linear ion trap– mass spectrometry (LC–QqLIT–MS) were developed for the determination of sulfonamide antibiotics and one N4-acetylated metabolite in environmental waters. The first of them was based on offline solid phase extraction, and special emphasis was devoted to the elimination of matrix components, evaluating three different extraction/purification strategies: single cartridges (Oasis HLB and Oasis MCX) and tandem (TD) extraction (combination of both). The second was based on on-line solid-phase extraction, and HLB cartridges were employed. In a parallel study, a new sensitive and selective method for the environmental trace analysis of triazines and triazine metabolites was developed. For this purpose, commercially available molecularly imprinted polymers (MIPS) were used fo the extraction and preconcentration of water and soils, followed by liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis. The suitability of the method was demonstrated through the analysis of several ground water and sludge-amended soils samples. In the last work developed, a novel plastic material Poly(ethylene-co-vinyl acetate-co-carbon monoxide) (PEVAC) was used as an absorptive passive equilibrium sampler and evaluated with regard to its ability to assess the bioavailable concentration of polar organic compounds (POCs) in laboratory experiments and in wastewater from a sewage treatment plant and compared with existing Solid-phase extraction techniques (SPE). 1. General Remarks Trace and ultra-trace analysis of polar organic contaminants in environmental samples generally requires a pretreatment step to isolate and enrich the target analytes, and also to reduce the matrix interference prior to chromatographic separation. Solid phase extraction (SPE) is usually the technique of choice for 4 the simultaneous extraction and concentration of many organic compounds present in aqueous samples (1, 2, 3). Despite their attractive features, the classical SPE sorbents retain analytes by physicochemical interactions that lead to co-extraction o f other matrix components and interfering substances, such as fulvic and humic acids (4,5). Furthermore, when using liquid chromatography-mass spectrometry (LCMS) for analysis, signal suppression or enhancement occurs when matrix components are coeluted with the analyte(s), especially using electrospray ionization (ESI) mode. Molecularly imprinted polymers (MIPs) have been proved to be an useful alternative to overcome the drawbacks of traditional SPE sorbents and immunosorbents (6,7,8). This adsorptive polymers are prepared by a molecular imprinting technique, in which a functional monomer is polymerized with a cross-linker in the presence of a template molecule. The removal of the template molecule from the resulting polymer leaves molecularly imprinted complementary binding sites for the template molecule wich will be mainly retained by specific interactions with functional groups such as hydrogen bonds, dipole-dipole forces and ion exchange interactions (9). MIPs are therefore used as selective sorbents in the SPE extraction of target analytes in complex matrices. On the other hand, it has been shown that organic compounds tend to bind to particulate organic matter (POM) and dissolved organic matter (DOM) present in environmental water, making the organic compounds less prone to partitioning with biota (10,11,12,13). In contrast to adsorptive polymers such as the MIPs, absorptive polymers have a glass transition temperature (Tg) below the temperature of employment, which causes the absorptive material to operate as a homogenous, non-porous liquid in which the analytes will be retained by dissolution rather than by specific interactions with the surface of the polymer (14). This feature allows the absorptive material to equilibrate with the surrounding medium without reaching saturation (15), in contrast to adsorptive polymers, commonly used in SPE. 2. Extraction and purification of environmental samples. 2.1. Sulfonamides in natural water samples 2.1.1 Offline SPE The occurrence of 9 sulfonamides and one acetylated metabolite in different environmental waters (waste water, surface water, ground water) and mineral water, was assessed through three different SPE approaches and subsequent analysis with LC-QqLIT-MS, using two different adsorptive materials: Oasis 5 HLB cartridges of 200 mg (60 mL) and Oasis MCX cartridges of 150 mg (60 mL) from Waters ( Milford, MA, USA), and a tandem between both of them. The analytical protocol is detailed in Annex A. 2.1.2 Online SPE The presence of 19 selected sulfonamides, including one acetylated metabolite, in ground water samples taken from surveillance and operational monitoring networks located in two ground water bodies in Catalonia was studied. A new analytical methodology based on online SPE–LC–MS/MS was used. Briefly, the on-line preconcentration of samples, aqueous standards and operational blanks was performed using an automated on-line SPE sample processor (Prospekt-2 TM (Spark Holland, Emmen, The Netherlands). 40 mL of ground water samples were extracted using Oasis HLB cartridges fromWaters (Milford, MA, USA). The analytical protocol is detailed in Annex A. 2.2. Triazines and triazine metabolites in soils and natural waters The presence of nine triazines (chlorotriazines), including three dealkylated metabolites, was studied through the use of MIP4SPE Triazine10 MIP cartridges (terbuthylazine-imprinted polymer, 25 mg, 10 mL) for the isolation and purification of both water and soil samples. These cartridges were kindly provided by MIP Technologies AB (Lund, Sweden). The analysis was carried out by LC-QqLIT MS. To avoid potential contamination from residues of the MIP template molecule, the analysis of terbuthylazine was carried out through the determination of its metabolite deethylterbutylazine. The MIP used was commercially available, which considerably simplifies the pre-treatment step and guaranties the reproducibility between batches of the cartridges to be used. To assess the selectivity of the MISPE procedure developed for the extraction of triazines and structurally related compounds, two OPPs, chlorpyrifos and diazinon, were also included as target analytes. The analytical protocol is detailed in Annex B. 2.3. Polar organic compounds in waste waters A novel plastic material Poly(ethylene-co-vinyl acetate-co-carbon monoxide) (PEVAC, Figure 1) was developed to test its ability to assess the bioavailable concentration of a variety of POCs in laboratory experiments and in wastewater from a sewage treatment plant. Imidacloprid, carbendazim, atrazin, diazinon, chlorpyrifos, carbamazepine and metoprolol were the compounds selected for the 6 bioavailability experiment. Paracetamol (acetaminophen) , oxazepam , carbamazepine and metoprolol were the pharmaceuticals selected for the waste water experiments. The results were compared with existing SPE techniques, using different SPE materials (Oasis MCX and MAX SPE cartridges, and ENV+ cartridges). FIGURE 1. The PEVAC polymer (Tg=-32ºC), with the weight ratio of x=66 Wt%, y=24 Wt% and z=10 Wt% The analytical protocol is detailed in Annex C. 1. RESULTS 3.1. Sulfonamides 3.1.1. Offline SPE-LC-QqLIT-MS Detailed information regarding the method optimization, recovery values obtained for each adsorptive material etc can be found in reference 16. For both offline and online SPE methodologies, quantification was performed based on peak areas and using an internal standard calibration method, crucial to correct potential matrix effects. The highest sulfonamide concentrations were those corresponding to surface water from the Llobregat River, likely due to the many agricultural areas located upstream of the sampling point, as well as to the proximity of Barcelona city. Figure 2 shows the chromatograms corresponding to one of the three replicates of the surface waters taken during the first campaign (C1). 7 Figure 2. Total ion current and ion chromatograms corresponding to the SPE extraction and LC–QqLIT–MS analysis of a natural surface water sample from the Llobregat River. 8 As expected, the lowest concentrations corresponded to the bottled mineral water and the ground water of Barcelona, in which nearly all the sulfonamides detected were below the LOD (see Annex A). Sulfadimethoxine was the most frequently SAs residue detected; being present in all water samples, even in the mineral and groundwater (16). Sulfamethoxazole was also often detected in natural waters and at high concentrations (maximum 1488 ng L−1), likely because it is used in both human (anti-acne agent) and veterinary medicine (antibiotic and growth promoter). Despite that, the highest concentration found in the natural water samples corresponded to sulfapyridine, which was found to be present in river water up to 12,000 ng L−1. 3.1.2. Online SPE-LC-QqLIT-MS Ground water samples were taken in spring 2008 in two ground water bodies in Catalonia. A total of 65 wells were sampled, including monitoring wells and natural springs. Ground water was sampled from depths ranging from 3 to 206 m. Further information regarding the optimization of the online SPE procedure can be found in reference 17. Table 1. Descriptive univariate statistics of the data. SD,: standard deviation; *:municipalities and ground water bodies correspond to the location of the maximum concentration value detected for each sulfonamide. Contaminants such as sulfonamides and nitrates, highly soluble in water, may reach the water table and be transported by the slowly moving ground water, widening its presence through very extensive ground water systems. Since sulfonamides are related to livestock veterinary practices, they could be used as a specific indicator of manure contamination (18). Nitrogen in its different species (organic, ammonium, nitrite and nitrate) is a major constituent of manure, and, similarly to sulfonamides, is very soluble in water. Increased concentrations of nitrate that result from both nitrification of ammonium or direct introduction from mineral fertilizers are commonly present in both ground water and surface water associated with ammended agricultural lands. As nitrates and sulfonamides detected in ground waters 9 may share a common origin (extensive and intensive cattle farming and manure application in crop lands), the possibility of establishing a correlation between both parameters was worth to consider. The depth of the sampling site and total organic carbon (TOC) were also considered to play an important role in the concentration distribution of both nitrates and sulfonamide concentrations. With this aim, pair wise correlations between nitrates concentration, depth of the well and sulfonamides concentration were estimated and are given in Table 2. Regarding nitrates and sulfonamides, a clear correlation between the occurrence of both could not be established from the data obtained. Sulfadiazine and sulfamethizole are the two sulfonamides with the highest correlation coefficients regarding nitrates concentration (0.37 and 0.33, respectively). However both sulfadiazine and sulfamethizole were the compounds with the lowest frequencies of detection in both ground water bodies ( see Table 1). Therefore, the relationship between both nitrates and these antibiotics should be investigated in further detail. Table 2. Relationship between depth, nitrate and sulphonamide concentrations, expressed as pairwise correlation coefficients. The variables are the concentrations of the corresponding sulfonamides (see reference 18). Higher pairwise correlations are marked in bold. 3.2. Triazines Detailed information regarding the recovery studies and results for the target triazines can be found in reference 19. Results listed in Table 3 showed that simazine was the most ubiquous analyte in ground water and at the highest concentrations, with values up to 105.11 ng L-1. This value was above 100 ng L-1, the boundary value established in the Directive 98/83/EC for the total amount of pesticides in drinking water. The other analytes were less frequently detected and at much lower concentrations. For instance, atrazine was found in three out of the seven wells sampled and DEA and DET in two of them. Propazine 10 and prometon were detected only in one ground water sample, and sebuthylazine and cyanazine were not detected. Three soil samples from different agricultural areas fertilized with sludge from a near wastewater treatment plant, and one sample of that sludge were analyzed. The highest concentrations were found Figure 3: Comparison between the chromatograms of a sample extracted using the triazine MIP and a nonimprinted polymer extracting material in a HPLC grade water sample spiked at 2.5 ng L-1 . in the most recently sludge-fertilized soils, S1 and S3 (see Table 4). Sebuthylazine was the analyte detected at the highest concentrations, with values in the range 0.46-2.26 ng g-1. Propazine was detected at the lowest levels, from 0.05 to 0.11 ng g-1. Sludge showed the lowest concentrations of triazines (0.010.28 ng g-1); this evidenced that the contribution to the pesticide load from the sludge was not comparable to the input by means of spreading of pesticides over the fields. The fact that more recently fertilized soils contained higher concentration of pesticides might be due to the combined actions of spreading and simultaneous sludge application at the same stage of the crop. 11 Table 3: Concentrations (ng L-1) in the ground water samples investigated. - : below the method limit of detection. Table 4: Concentrations (ng kg-1) in the sludge and the sludge fertilized soils investigated. 3.3. Polar organic contaminants 3.3.1. Evaluation of fulvic acid enrichment on the PEVAC sampler and on a polar resin based SPE cartridge. Conventional SPE-methods are designed to quantify the total amount of an analyte from the sample matrix. The SPE-technique has two major drawbacks when assessing the freely dissolved fraction of POCs. First, the exhaustive extraction approach may disturb the initial distribution of the analytes between water, DOM and POM in the sample (15). Secondly, polar resin based cartridges for efficient recovery of POCs will also extract DOM (2), making it impossible to distinguish the DOM-bound fraction of an analyte from the freely dissolved fraction. The chromatogram obtained from the SPE extraction of FA rich water in this work presented the accumulated FA as a broad hump extending from 1.5 to 4.0 minutes (Figure 4a). The summed massspectrum of the hump further confirmed the presence of FA in the extract. Thus, it is impossible to differentiate the contribution to a chromatographic peak of a chemical, which can originate both from the freely dissolved concentration (CFree) and from the FA bound concentration. The removal of humic substances in an extraction method is therefore crucial when it comes to assessing the CFree of a substance present in aquatic environments. A summed mass spectrum over the same area and retention time as the hump in the SPE chromatogram was was also constructed from the chromatogram obtained from the PEVAC sampler. The mass spectrum revealed the absence of FA in the PEVAC extract (Figure 4b), which indicates that measurements performed with the PEVAC sampler will represent the truly dissolved 12 concentration of contaminants in FA rich water given that negligible depletion is achieved. The same result has earlier been reported, where the SPE method gave a humic associated hump in the beginning of the chromatogram which disappeared when supported liquid membrane (SLM) extraction was applied, a precursor to the ESTM sampler, on a HS rich river water (20). Figure 4. The ability to enrich fulvic acid on a; a. polar resin based SPE cartridge, b. on a PEVAC sampler 3.3.2. Influence of fulvic acid or suspended sediment on the freely dissolved concentration of POCs The knowledge that measurements performed with the PEVAC sampler assess mainly the CFree of chemicals in environmental water, make it possible to evaluate the abundance of the seven POCs to DOM and POM. Figure 5a, show that only Metoprolol out of the seven POCs presented a decrease in CFree as the amount of FA in the water increased. The result can seem confusing when earlier findings has reported the binding between contaminants and DOM to rely on hydrophobic interaction (10), and metoprolol is one of the less hydrophobic compound out of the seven. However, Lützhøft and co-workers et al 2000 (22) 13 investigated ionisable compounds ability to bind to DOM in water at different pH. They found that the ability for a compound to bind to DOM is highly dependent on pH and that organic cations can electrostatically interact with anionic sites present in the FA structure at pH >4. Metoprolol is the only compound of the investigated seven substances having a pKa sufficiently low to make it mainly protonated and positively charge at pH 7. Thus ionic bonding between Metoprolol and DOM is a plausible explanation for the drastic decrease in CFree as the FA concentration is increased, since the FA used in the experiment becomes deprotonated at pH > 3.8. However, a decrease in CFree based on just hydrophobic interaction with DOM is not likely for a compound with Log Kow< 5 (11), why no visible decrease is seen for the other six compounds as the FA concentration increased. Figure 5. The freely dissolved concentration (CFree) of the seven selected compounds as a function of; a. the amount of fulvic acid in water, b. the amount of sediment in water Important to note in the former experiment is that the water concentration of all the POCs were constant throughout the experiment independently of the added amounts of FA indicating that negligible depletion was achieved, except for diazinon and chlorpyrifos, where none of the fifteen samples proved to have detectable levels of the two contaminants (Data not presented). Diazinon and chlorpyrifos were probably depleted from the water phase due to the high enrichment factor in the PEVAC film, which in turn makes the estimation of them unreliable. However, if the amount of a chemical bound to DOM or POM is much greater than the amount finally absorbed by the sampler a temporary depletion of the chemical in the water phase is allowed, because when steady state in the sample is finally stabilized, net-desorption from the DOM or the POM will re-establish the initial CFree in the water phase. In these cases it is the DOM or the POM and not the water that represents the matrix that should not be depleted (21). When the FA, representing the DOM, was replaced with sediment, the CFree of all the seven POCs was more or less affected by the increasing amount of sediment in the water sample (Figure 5b). Chlorpyrifos and diazinon showed a significant decrease in CFree as the sediment concentration increased, probably due to hydrophobic interaction with fattier and higher amount of TOC in the sediment experiment than in the DOM experiment. The decrease in CFree for metoprolol was even more pronounced when the sediment 14 concentration was elevated compared to the increase of DOM in the earlier experiment. The results suggest that sediment contain charged groups other than the deprotonated carboxylic groups represented in the FA. Solid particles and minerals often have negative sites exposed on their surface that will interact with positively charged organic and inorganic ions (25, 26). The excess of negatively charged sites on particulate surfaces may explain why the CFree of carbendazim drastically dropped when the sediment concentration increased in comparison with the previous DOM experiment. The major part of carbendazim is represented in its neutral form at pH 7, but since it has a pKb-value of 6.09, around 10% will be protonated and positively charged at pH 7. The irreversible interaction between the positively charged carbendazim and the excess of negatively charged sites in the sediment will deplete the initial ionic fraction of carbendazim from the aqueous phase. The remaining neutral fraction of carbendazim in the aqueous phase will then gradually be rearrange into more positively charged ions interacting with the sediment until the freely dissolved fraction of carbendazim is depleted or until the surface of the sediment is saturated. The water concentrations of the seven POCs throughout the sediment experiment were not possible to establish due to a high amounts of dispersed particulate matter in the water phase. The conclusion is that total extraction is a sufficient method to estimate the freely dissolved concentration of uncharged POCs in natural water. Furthermore, the work illustrated that the PEVAC polymer can be an alternative material to silicone and PA when it comes to estimating the bioavailable concentration of POCs in environmental matrices. 3.3.3. Sampling of wastewater from a sewage treatment plant. For three of the four pharmaceuticals utilized in the experiment the two sampling techniques showed no significant difference in estimating the freely dissolved concentration of the compounds through out the sewage treatment plant (Figure 6 - 8). The result showed that a total organic carbon (TOC) with an average of 150 mg/L in the influent water and 9.6 mg/L in the effluent water is too low to, other than marginally, influence the freely dissolved concentration (CFree) of the pharmaceuticals. The fourth compound metoprolol, which is the only compound out of the four pharmaceuticals that is cationic under the prevailing pH condition, revealed a decrease of 43% in freely dissolved concentration (C Free) in the influent water when quantified utilizing the PEVAC sampler and compared to the result from the SPE extraction (Figure 9). 15 Figure 6. A comparison of paracetamol concentrations in treated and untreated waste water established with SPE and PEVAC extraction techniques. Figure 7. A comparison of Carbamazepine concentrations in treated and untreated wastewater established with SPE and PEVAC extraction techniques. The result corresponds reasonably well with the previous laboratory experiment, regarding the influence of FA on the freely dissolved concentration of metoprolol (Figure 5a). However, the activated sludge and sand filter processed effluent water showed an increase of the bioavailable concentration of metoprolol of 366% when the PEVAC sampler was utilized compared to the result from the SPE extraction (Figure 9). The enhanced bioavailable concentration of metoprolol in the effluent water appears to contradict previous results. However, under the laboratory investigation the pH was constant (Figure 5a), which was not the case in the sampling of the wastewater. An increase of pH in the effluent water would severely change the distribution between the ionic and non-ionic fraction of metoprolol in the water phase and thus the absorbent/water partition coefficient (KAbs/W) (See deliverable 2.2.17). 16 Figure 8. A comparison of oxazepam concentrations in treated and untreated wastewater established with SPE and PEVAC extraction techniques. If only the non-ionic fraction of metoprolol is assumed to partition with the absorbent of the PEVAC sampler an increase of pH from 7.8 in the influent water to 8.4 in the effluent water would lead to a 355% increase in non-ionic fraction of metoprolol and thus a 355% increase of KAbs/W . However, the Kabs/w used for the sewage water was the one that was determined at pH 7, thus the elevated concentration of metoprolol should be regarded as an artefact. This demonstrates the importance of using the appropriate Kabs/w, especially for charged species, when applying this sampling technique to real samples. Figure 9. A comparison of metoprolol concentrations in treated and untreated wastewater established with SPE and PEVAC extraction techniques. The analysis of the waters showed that activated sludge, sand filtration in combination with ozone treatment was the most effective approach to eliminate pharmaceuticals from the wastewater (Figures 6 to 9). Activated sludge and sand filtration alone (effluent) as well as membrane bioreactor (MBR) was not sufficient treatment to significantly reduce the freely dissolved concentration (C Free) of the selected 17 compound in the wastewater, except in case of paracetamol, for which a drastic decrease was observed with all applied treatment techniques. CONCLUSIONS First, the two developed methods (following offline and online SPE strategies) were proved to be powerful tools for the analysis of sulfonamides and N4-acetylated metabolites in complex natural waters, allowing determining concentrations down to the ng L−1 level in all kind of waters (wastewater, groundwater, surface and bottled mineral water). Results on groundwater and mineral bottled water constitute the first data reported on levels of SAs in these types of waters. On the basis of these outcomes, the N4-acetylated metabolites of sulfonamide antibiotics should be considered in environmental residue analysis to avoid the underestimation of the elimination rates of SAs during wastewater treatments. In the offline SPE study, N4-acetylsulfamethazine was detected in all the samples at concentration up to 316 ng L−1 ( concentration detected in surface water). Regarding the online SPE methodology applied, 18 out of the 19 target sulfonamides were detected in the two ground water bodies from Catalonia studied, being sulfadimethoxine and sulfamethazine, commonly used in veterinary practices, those occurring more frequently. It should be highlighted again the high frequency of detection for the acetylated metabolite N4-acetylsulfamethazine, comparable to the highest frequencies aforementioned. The need for the inclusion of this and other metabolism products in future monitoring studies is unquestionable. Despite the peak concentration values detected in different sampling sites, the average detected concentrations of sulfonamides are generally below 50 ng/L. Sensitivity is therefore one of the most critical parameters in order to obtain unequivocal and reliable determination for he compounds investigated. When performing on-line SPE analysis, its fully automation and the minimum sample manipulation requirements permits the enhancement of sensitivity, as the whole sample volume (40 mL) gets to the chromatographic system instead of a final reconstituted extract as in off-line procedures, where usually volumes of 200 mL or bigger are reduced to approximately 0.5 mL and only around 10 µL will be injected in the mass analyzer. Despite the low sample volumes required in on-line procedures, it has been proved that sensitivity is not affected but, on the contrary, improved considerably, with limits of detection down to the pg/L level. Besides, LC– MS/MS allows for an unequivocal identification of the target sulfonamides. From the results obtained, no strong correlation between sulfonamides and nitrates concentrations could be established. Whereas nitrates in ground water are originated from fertilizers of both animal and mineral origin, sulfonamides could be specifically considered as potential indicators of pollution from animal origin. For this reason, and because data on nitrates is historically richer and more consistent, the presence of sulfonamides in ground water matrices should be investigated in further detail in order to propose these substances as reference points to indicate pollution from animal farm and agriculture practices. 18 Regarding triazines and the use of MIPS, the outcomes obtained evidenced the excellent affinity and selectivity provided by the Triazine 10 MIP used in the extraction and purification of complex environmental samples containing triazines and structurally related compounds (see Annex B) .The use of the LC-MS/MS developed method afforded high sensitivity (LODs in the low ng L-1and ng g-1) and allowed an unequivocal identification (in SRM mode) of the triazines investigated. The QqLIT hybrid mass analyzer was the most suitable tool for detection and determination of trace levels of triazines in complex environmental samples, especially in connection with MISPE isolation and purification. The levels of the target pesticides found in the natural water analyzed were below the limit established by the European Legislation for drinking water, except for one ground water sample, where concentrations detected for simazine and atrazine were 105.11 ng L -1 and 35.37 ng L-1 respectively. For some of the compounds studied (DIA, DEA, atrazine, prometon, cyanazine), concentrations found in water were similar to the values detected in soils (0.01-2.26 ng g-1), but the majority were below 0.50 ng g-1. Pesticide concentrations in the sludge applied as fertilizer were generally low, which indicated that the contribution of the sludge to the total amount of pesticides in the sludge-fertilized agricultural soils was not as relevant as the direct pesticide application to fields. Freely dissolved concentrations determined from equilibrium sampling of uncharged polar organic compounds using the novel sampler compared well with the total concentration measurements obtained with the serial SPE method. The results further indicate that the freely dissolved concentrations are lower, although not drastically lower, than the total concentrations. For species that are mainly ionic, we conclude that in the case that distribution coefficients are lacking for the prevailing pH, in situ equilibrium sampling is not recommendable. Instead, equilibrium sampling and quantitation using grab samples in combination with the use of either isotopically labelled surrogate standards or, alternatively, a standard addition approach is recommended. Furthermore, biological treatment of municipal waste water in combination with sand filtration and ozone treatment showed promising results regarding removal of pharmaceutical residues. 19 REFERENCES (1) Sancho, J. V.; Pozo O. J.; Hernández F. Liquid chromatography and tandem mass spectrometry: a powerful approach for the sensitive and rapid multiclass determination of pesticides and transformation products in water. Analyst. 2004, 129, 38-44. (2) Masqué, N.; Marcé, R. M.; Borrull, F. New polymeric and other types of sorbents for solid-phase extraction of polar organic micropollutants from environmental water. Trends in Analytical Chemistry. 1998, 17, 384-394. (3) Bagheri, H.; Saraji, M.; Barceló, D. Evaluation of polyaniline as a sorbent for SPE of a variety of polar pesticides from water followed by CD-MEKC-DAD. Chromatographia. 2004, 59, 283-289. (4) Koeber, R., Fleischer, C., Lanza, F., Boos, K.S., Sellergren, B. and Barcelo, D., Evaluation of a multidimensional solid-phase extraction platform for highly selective on-line cleanup and highthroughput LC-MS analysis of triazines in river water samples using molecularly imprinted polymers. Anal. Chem., 2001. 73(11): 2437-2444. (5) Villagrasa, M., Guillamon, M., Eljarrat, E. and Barcelo, D., Matrix effect in liquid chromatography-electrospray ionization mass spectrometry analysis of benzoxazinoid derivatives in plant material. J. Chrom. A, 2007, 1157(1-2): 108-114. (6) Chapuis, F., Pichon, V. and Hennion, M.C., Molecularly imprinted polymers: Developments and applications of new selective solid-phase extraction materials. LC GC Europe, 2004, 17(7): 408+. (7) Chapuis, F., Pichon, V., Lanza, F., Sellergren, S. and Hennion, M.C.,. Optimization of the classselective extraction of triazines from aqueous samples using a molecularly imprinted polymer by a comprehensive approach of the retention mechanism. J. Chrom A, 2003,999(1-2): 23-33. (8) Pichon, V., Selective sample treatment using molecularly imprinted polymers. J. Chrom. A, 2007, 1152(1-2): 41-53. (9) Filippov, O. A.; Tikhomirova, T. I.; Tsizin, G. I.; Zolotov, Y. A. Dynamic preconcentration of organic substances on nonpolar adsorbents. J. Anal. Chem. 2003, 58, 398-422. (10) Traina, S. J.; Mcavoy, D. C.; Versteeg, D. J. Association of linear alkylbenzenesulfonates with dissolved humic substances and its effect on bioavailability. Environ. Sci. Thchnol. 1996, 30, 1300-1309. (11) Chin, Y. P.; Weber, W. J., Jr.; Eadle, B. J. Estimating the effects of dispersed organic polymer on the sorption of contaminants by natural solids. 2. Sorption in the presence of humic and other natural macromolecules. Environ. Sci. Thchnol. 1990, 24, 837-842. (12) Day, K. E. Effects of dissolved organic carbon on accumulation and acute toxicity of fenvalerate, deltamethrin and cyhalothrin to Daphnia magna (straus). Environ. Toxicol. Chem. 1990, 10, 91101. 20 (13) Boa, M. L.; Dai, S. G.; Pantani, F. Effect of dissolved humic material on the toxiciy of tributyltin chloride and triphenyltin chloride to Daphnia magna. Environ. Contam. Toxicol. 1997, 59, 671676. (14) Baltussen, E.; Cramers, C. A.; Sandra, P. J. F. Sorptive sample preparation – a review. Anal. Bioanal. Chem. 2002, 373, 3-22. (15) Mayer, P.; Tolls, J.; Hermens, J. L. M.; Mackay, D. Equilibrium sampling devices. Environ. Sci. Technol. 2003, 37, 184A-191A. (16)García Galán, M.J., Díaz-Cruz, S., Barceló, D. Highly sensitive simultaneous determination of sulfonamide antibiotics and one metabolite in environmental waters by liquid chromatographyquadrupole linear ion trap-mass spectrometry. J. Chrom. A.2008, 1193, 50-59. (17)García Galán, M.J., Díaz-Cruz, S., Barceló, D. Determination of 19 sulfonamides in environmental waters by automated on-line solid phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) (submitted) (18)García Galán, M.J., Garrido, T., Fraile, J., Ginebreda, A., Díaz-Cruz, S., Barceló, D. Simultaneous occurrence of nitrates and sulfonamide antibiotics in two ground wáter bodies of Catalonia (Spain). J. Hydrology, 2009 (accepted). (19)García Galán, M.J., Díaz-Cruz, S, Barceló, D. Determination of triazines and their metabolitesin environmental samples using molecularly imprinted polymer extraction, pressurized liquid extraction and LC-tandem mass spectrometry. J. Hydrol., 2009, (accepted). (20) Megersa, N.; Solomon, T.; Jönsson, J. Å. Supported liquid membrane extraction for sampling work-up and preconcentration of methoxy-s-triazine herbicides in a flow system. J. chromatogr. A. 1990, 830, 203-210. (21) Heringa, M. B.; Hermens, J. L. M. Measurements of free concentrations using negligible depletion-solid phase microextraction (nd-SPME). Trends in Analytical Chemistry. 2003, 22, 575-587. (22) Lützhøft, H. C. H.; Vaes, W. H. J.; Freidig, A. P.; Halling-Sørensen, B.; Hermens, J. L. M. Influence of pH and other modifying factors on the distribution behaviour of 4-quinolones to solid phases and humic acids studied by “Negligible-Deplition” SPME-HPLC. Environ. Sci. Technol. 2000, 34, 4989-4994. (23) Reichenberg, F.; Mayer, P. Two complementary sides of bioavailability: accessibility and chemical activity of organic contaminants in sediments and soils. Environ. Toxicol. Chem. 2005, 25, 1239-1245. (24) Semple, K. T.; Doick, K. J.; Jones, K. C.; Burauel, P.; Craven, A.; Harms, H. Defining bioavailability and bioaccessibility of contaminated soil and sediment is complicated. Environ. Sci. Technol. 2004, 38, 228A-231A. 21 (25) Schwarzenbach, R. P.; Gschwend, P. M.; Imboden, D. M. Environmental Organic Chemistry. Second ed. John Wiley & Sons Inc. Hoboken, New York, 2003. (26) Haderlein, S. B.; Schwarzenbach, R. P. Adsorption of substituted nitrobenzenes and nitrophenols to mineral surfaces. Environ. Sci. Technol. 1993, 27, 316-326. ANNEX A ANALYTICAL PROTOCOLS FOR THE ANALYSIS OF SELECTED SULFONAMIDES IN DIFFERENT NATURAL WATERS 1. CHEMICALS Organic solvents: Methanol, Acetone, Acetonitrile, all HPLC grade Water HPLC grade Formic acid. Sulfonamides: o Offline SPE procedure: sulfadiazine, sulfadimethoxine, sulfamethazine, sulfamethizole, sulfamethoxazole, sulfamethoxypyridazine, sulfapyridine, sulfisoxazole, sulfathiazole and N4-acetylsulfamethazine. o Online SPE procedure: the sulfonamides aforementioned plus sulfadimidin, sulfamerazine, sulfacetamide, sulfabenzamide, succinyl-sulfathiazole, sulfaguanidine, sulfanitran, sulfaquinoxaline and sulfadoxine. Oasis HLB and MCX SPEcartridges (Waters). 2. SAMPLE COLLECTION AND PRETREATMENT Surface water samples were taken from the Segre River (Lleida, Spain) and Anoia River (Barcelona) in June 2006. Samples from the wastewater treatment plant (WWTP) in Lleida were also sampled in June 2006. In May 2007 groundwater from the city of Barcelona was also sampled. Bottled mineral water was purchased from a supermarket. Environmental water samples, around 1 L, were shipped to our laboratory under cool conditions in amber glass bottles pre-rinsed with HPLC grade water in a portable refrigerator, readily vacuum filtered through 2.7 µm glass fiber filters followed by 0.45 µm nylon membrane filters (Whatman, Maidstone, UK) and stored at 4 ◦C until analysis (less than 2 days). Under such conditions ny antibiotic activity in the samples was kept to the minimum. In the offline SPE procedure, three sample replicates were taken for each water matrix. Ground water samples for the online SPE procedure were taken in spring 2008 in two ground water bodies in Catalonia: Plana de Vic and La Selva. Water samples were collected in amber polyethylene terephthalate (PET) bottles and transported to the laboratory under cooled conditions (4 ºC). Once there, samples were filtered through 0.45 lm Nylon filters to eliminate suspended solid matter and then stored at 22 4 ºC in the dark until analysis which was always carried out within 48 h of collection to avoid microbial degradation. 3. SOLID PHASE EXTRACTION The analytical protocol followed for the SPE extraction was adapted from a methodology previously developed and applied by the authors in the purification of pressurized liquid extracts of sludge samples for the analysis of SAs. Figure 1 shows the three protocols followed. The method using the HLB cartridges was shown to be the most efficient. Under the selected procedure, 400mL of water samples (200mL for waste water) were loaded at 3mL min−1 onto Oasis HLB cartridges preconditioned with 3mL of MeOH in 50mM HCOOH, followed by 3mL of acetone in 50mMHCOOH and 2mL of HPLC grade water at neutral pH with a 5% ofMeOH. After the sample extraction, the cartridges were rinsed with 2mL of HPLC grade water at neutral pH with a 5% of MeOH, to remove potential interferences. Finally, cartridges were dried under vacuum (around 30 min.) and then eluted with 6mL of MeOH in 50mM HCOOH plus 6mL of acetone in 50mM HCOOH at 3mLmin−1. The resulting eluates were brought to dryness under a gentle N2 stream and reconstituted with 400µL of MeOH containing d4-sulfathiazole as internal standard, for further analysis. Regarding the online SPE protocol, the procedure had been optimized in a previous work (REFERENCE) the on-line preconcentration of samples, aqueous standards and operational blanks was performed using an automated on-line SPE sample processor Prospekt-2 TM (Spark Holland, Emmen, The Netherlands). The online Oasis HLB cartridges were conditioned with 1 mL of a mixture of methanol/acetone (1:1 v/v) at a rate of 1 ml min-1 and equilibrated with 1mL of water.40 mL of the ground water samples were loaded onto the cartridges, which were washed afterwards with 1 mL of water at a flow rate of 1 mL min1 to improve the complete transfer of the sample and remove interferences. Cartridges are then transferred to the elution clamp and the analytes are eluted directly onto the LC column by the HPLC and the gradient solvents. 23 Figure 1. Different solid-phase extraction strategies followed: (a) HLB cartridges, (b) MCX cartridges and (c) tandem extraction (HLB and MCX). 24 4. ANALYTICAL DETERMINATION Instrument: HP 1100 chromatograph (Agilent Technologies, Palo A, CA, USA) coupled to a 4000 QTRAP mass spectrometer (Applied Biosystems, Foster City, USA) equipped with a turbospray electrospray source. LC column: Atlantis C18 (Waters, 150 mm x 2.1 mm, 3 µm) preceded by a guard column with the same packing material. Ionization: positive ionization mode (PI). Gradient elution: mobile phase of HPLC grade water and acetonitrile, both slightly acidified with 1mM formic acid. The gradient is programmed from 25% to 100% of the organic phase in 11 minutes, held for two minutes and returned to the initial conditions in 10 minutes. Flow rate: 0.2 mL min-1 Injection volume: (offline procedure): 20 µL. 5. METHODS VALIDATION Calibration curves: internal standard calibration based on peak areas (concentrations ranging between 0.05 and 1000 ng L−1) Method recoveries (offline SPE method): please,see reference 16. Limits of detection and quantification: please, see Table 1 for the offline SPE procedure and Table 2 for the online SPE procedure. Table 1. Recovery rates obtained for the Oasis HLB approach, precision, expressed as relative standard deviation RSD (%), and method limits of detection and quantification for the different water matrices studied. Recovery values below 50% or over 150% were neglected (–). 25 Table 2. Performance of the on-line SPE–LC-QqLIT–MS method applied. r2, correlation coefficient; LOD, method limit of detection; LOQ, method limit of quantification and RSD, relative standard deviation (%). ANNEX B ANALYTICAL PROTOCOL FOR THE ANALYSIS OF TRIAZINES AND TRIAZINE METABOLITES IN WATER AND SOIL SAMPLES. 1. CHEMICALS: Organic solvents: methanol, acetonitrile, dichloromethane (DCM), all HPLC grade Water HPLC grade Pesticides: atrazine, simazine, cyanazine, sebuthylazine, deisopropylatrazine (DIA), deethylatrazine (DEA) and deethylterbuthylazine (DET), prometon, propazine, chlorpyrifos and diazinon d5-atrazine (100 μg mL-1, acetone) and the surrogate standard d5deisopropylatrazine Hydromatrix (Varian) Oasis HLB cartridges (Waters) MIP4SPE Triazine10 MIP cartridges (terbuthylazine-imprinted polymer, 25 mg, 10 mL) 26 2. SAMPLE COLLECTION AND PRETREATMENT Ground water, tap water and HPLC grade water were the selected samples for this study. Tap water from the city of Barcelona (Catalonia, Spain) and ground water from seven wells along the province of Barcelona were taken in March 2007. Ground water samples (1 L each) were shipped to our laboratory under cool conditions (4ºC) in amber glass bottles pre-rinsed with HPLC grade water in a portable refrigerator, readily vacuum filtered through 2.7 m glass fiber filters followed by 0.45 m nylon membrane filters and stored at 4 ºC until analysis (less than two days). Tap water samples were taken the day before the analysis and were not filtered. Three sample replicates were taken in all cases. Soil samples were collected at the end of October 2005 at selected sites from different intensive horticulture areas in the proximity of Barcelona (Catalonia, northeast of Spain). The soil was calcareous type (c.a. 30% sand, 25% silt and 45% clay) with a pH 7-9 and a low to moderate content of organic carbon (0.9-3.5%). Representative sampling of the top soil (0-20 cm) was performed with an Auger sampler (Eijkelkamp, Giesbeek, The Netherlands) at a rate of five subsamples per hectare. Individual subsamples were shipped in aluminum foil packets to our laboratory under cool conditions (4º C) in a portable refrigerator. Subsamples corresponding to the same agricultural field were pooled, and then readily frozen at –20 ºC upon arrival. Samples were afterwards lyophilized, homogenized, sieved through a stainless steel 0.2 mm sieve and stored at –20 ºC in sealed containers until analysis. Subsamples of soil were taken from a site in the same area where sludge was not applied to the soil. This pooled sample was used as control blank soil. Samples of the sewage sludge applied in the soil fertilization process were also taken. 3. CLEAN UP Aliquots of 10 ml of the water samples were passed through the MIP cartridges previously conditioned with 1 mL of MeOH, 1 mL of HPLC grade water and 1 mL of 50 mM NH4H2PO4 solution at pH 3, at a 27 flow rate of 3 ml min-1 using a 12-fold vacuum extraction box (J.T. Baker, Phillipsburg, NY, USA). To avoid interferences and eliminate potential matrix effects, the cartridges were then washed with 1 mL 0.1 M HCl and 1 mL HPLC grade water. After that and in order to boost selective interactions between the MIP and the target analytes, 1.5 mL of DCM were loaded onto the cartridges. Vacuum (20 min) was applied before adding the DCM, since water and DCM are not miscible, and 2 min more after adding the DCM, to remove the remains of the solvent. As DCM is a weakly polar and aprotic solvent, it favors the interactions between the analytes and the binding sites, and simultaneously removes co-extracted substances from the MIPs. Finally, the cartridges were eluted with 3 mL MeOH at a slower flow rate than before (2 ml min-1). Since it is a very polar and protic solvent, it disrupts the hydrogen bonds between the polymer and the compounds, allowing the elution. The resulting eluates were evaporated under a gentle N2 stream at 25 ºC in a Turbo Vap LV evaporator (Zymark, Hopkinton, MA, USA), then reconstituted with 0.5 mL of LC mobile phase (methanol:water) at the initial conditions (10:90, v:v). The extraction of the solid samples was carried out by pressurized liquid extraction using an accelerated solvent extractor ASE 200 (Dionex). 2 g of the lyophilized and sieved soil/sludge samples were mixed with Hydromatrix (previously ultra-sonicated with a mixture of acetone:MeOH (50:50, v:v) three times during 10 min. each one) into an extraction cell sealed at both ends with glass-fiber filters. Extraction was performed with a mixture of MeOH:acetone (50:50, v:v) under the following experimental conditions: pressure, 1500 psi; temperature, 65 ºC; preheat time, 5 min.; static time, 5 min.; extraction time, 3 min.; flush volume, 60%; purge time, 60 s., and 3 extraction cycles. The PLE extracts were evaporated under a gentle N2 stream and reconstituted with a mixture of 1 mL MeOH and 19 mL HPLC grade water. 10 mL aliquots were then purified following the MISPE procedure previously optimized for the extraction of triazines from the water samples. 4. ANALYTICAL DETERMINATION Instrument: HP 1100 chromatograph (Agilent Technologies, Palo A, CA, USA) coupled to a 4000 QTRAP mass spectrometer (Applied Biosystems, Foster City, USA) equipped with a turbospray electrospray source. 28 LC column: Purospher STAR RP-18 endcapped (125 mm x 2 mm; 5μm) (Merck, Darmstadt, Germany) preceded by a guard column with the same packing material. Ionization: positive ionization mode (PI). Elution gradient: mobile phase of HPLC grade water and methanol. The gradient progressed from 10 % to 100 % of the organic phase in 22 min, held there for 3 minutes, returned to the initial conditions in 5 minutes and, finally, a reequilibration period of 5 min was programmed. Gradient flow rate: 0.2 ml min-1 Injection volume: 20µL. 5. METHOD VALIDATION Calibration curves: internal standard calibration based on peak areas (concentrations ranging between 0.01 - 40 ng mL- 1). Method recoveries (offline SPE method): please, see reference 19. Limits of detection and quantification: please, see reference 19. ANNEX C. ANALYTICAL PROTOCOL FOR THE ANALYSIS OF POLAR ORGANIC CONTAMINANTS. 1. CHEMICALS: Organic solvents: toluene, methanol, acetonitrile, dichloromethane (DCM). Ohers: acetic acid, formic acid, hydrochloric acid, ammonium bicarbonate, ammonium hydroxide solution (25%). Poly(ethylene-co-vinyl acetate-co-carbon monoxide) beads. Nordic Reference Fulvic acid POCs: Imidacloprid, carbendazim, atrazin, diazinon, chlorpyrifos, carbamazepine, metoprolol (tartrate salt), paracetamol (acetaminophen) , [2H5]Oxazepam (99% purity) , [2H10]Carbamazepine (98.2 atom% 2H) and [2H3]paracetamol (99.1% atom% 2H) . ENV+ columns (50mg, 60µm, 3mL) were purchased from Isolute (Hengoed, UK). Oasis MCX and MAX SPE columns (60 mg, 30 µm, 3 mL) 2. PROCEDURES 29 2.1. PEVAC sampler preparation. (See Deliverable 2.2.17) 2.2. Evaluation of fulvic acid enrichment on the PEVAC sampler and on a polar resin based SPE cartridge. Three 200mg PEVAC samplers were left in a glass-vessel filled with 3.0 litres of tap-water for 2 days under gentle stirring. The water was spiked with 50mg/L of FA and buffered to pH 7 with ammonium bicarbonate. After 2 days, when equilibrium was achieved, the PEVAC samplers were removed from the solutions and extracted with MeOH. The extract was evaporated to dryness under nitrogen at 40°C and redissolved in 200µl of MeOH: Milli-Q water (1:1). 20ml of the FA rich water solution was filtrated through a SPE cartridge containing 50 mg ENV +, a polar divinylbenzene-polystyrene (DVB-PS) based resin. The filtrate was extracted from the SPE cartridge using MeOH. The extract was evaporated to dryness under nitrogen at 40°C and redissolved in 200µl of MeOH: Milli-Q water (1:1). 2.3.Influence of fulvic acid or suspended sediment on the freely dissolved concentration of POCs. Fifteen glass-bottles were filled to the edge with 120ml of tap-water. The water was spiked with imidacloprid, carbendazim, metoprolol, atrazin, carbamazepine, diazinon and chlorpyrifos. In the DOM experiment various amounts of FA were added to the bottles, providing concentrations of 0, 5, 10, 50 and 100 mg/L of FA in the bottles. In the POM experiment various amounts of natural sediment, with a total organic carbon (TOC) content of 2.2%, were added to the bottles, providing concentrations of 0, 5, 10, 50 and 100 g/L of suspended sediment in the bottles. All the samples were buffered to pH 7 with ammonium bicarbonate. 20mg of dry PEVAC-film were added to each of the fifteen bottles in the two experiments. The glass-bottles were then rotated for 2 days, which was the pre-determined equilibrium time (See Deliverable 2.2.17). After 2 days, the PEVAC samplers were removed from the solutions and extracted with MeOH. The extract was evaporated to dryness under nitrogen at 40°C and redissolved in 100µl of MeOH. The remaining concentrations of the seven POCs in the water-sample spiked with FA was established, from each sampling occasion, by evaporating 1.0ml of water to dryness under nitrogen at 40°C and redissolve it in 100µl of MeOH 30 2.4.Sampling of wastewater from a sewage treatment plant 24-hour composite samples were collected during four days from Hammarby Sjöstad sewage treatment plant (STP), Stockholm, Sweden. The influent water was treated by a conventional activated sludge process, using a sludge residence time of five days, followed by sand filtration. Additionally, a fraction of the biologically treated effluent water was passed through an ozone treatment step, using 15 g O 3/m3 of wastewater. In a separate treatment process, influent water was transferred to a membrane bioreactor (MBR) (Kubota Submerged Membrane Unit), in parallel to the activated sludge treatment. Samples were collected from the influent stream, from wastewater treated by activated sludge and a final sand filter, from ozone treated effluent and from the MBR. The samples, collected in plastic bottles, were immediately frozen and stored at -20° C until further analysis. When thawed, samples collected from four different days were combined into one pooled sample. 2.5. SPE extraction of wastewater. The serial cationic-, anionic-exchange SPE method used for determination of pharmaceutical residues in waste water is described in detail by Lavén et al. (20). In short, wastewater samples were initially passed through a glass-microfibre filter to remove particulate matter. An aliquot of 50 mL was used for the analysis of effluent, ozone and MBR treated wastewater, whereas 25 mL of wastewater was sufficient for the analysis of influent water. Additionally, 25 mL of H2O was added to influent water samples. The sample was adjusted to pH 2 with HCl (37%), and deuterated surrogate standards of paracetamol, carbamazepine and oxazepam were added prior to the SPE step. Metoprolol standard was added as a standard addition to duplicate samples prior to the SPE extraction. The clean-up procedure results in three fractions containing basic (eg. oxazepam and metoprolol), neutral (e.g.,paracetamol and carbamazepine) and acidic analytes, respectively. The SPE fractions were evaporated to dryness under nitrogen at 40°C and redissolved in 500 µL of 20% acetonitrile, 0.1% formic acid, prior to LC-MS analysis. 2.6. PEVAC extraction of wastewater Glass-bottles were filled to the edge with 120ml of influent wastewater or effluent, ozone and MBR treated wastewater. Deuterated surrogate standards of paracetamol, carbamazepine and oxazepam were added to the bottle prior to sampling. 100mg of PEVAC-film were added to each of the glass-bottles in the experiments. The bottles were then rotated for 2 days, which was the pre-determined equilibrium time (See Deliverable 2.2.17). The samples were not pH-adjusted. 31 After 2 days, the PEVAC samplers were removed from the solutions and extracted with MeOH. The extract was evaporated to dryness under nitrogen at 40°C and redissolved in 100µl of MeOH, 0.1% formic acid, prior to LC-MS analysis. 3. ANALYTICAL DETERMINATION Instrument: ACQUITY Ultra performance Liquid Chromatograph (Waters, Milford, USA) coupled to a QTOF. LC column: Acquity HSS T3 C18 column (1.7 µm, 2.1x100mm). Gradient elution: mobile-phase mixture of 95% Milli-Q water and 5% acetonitrile (ACN) buffered with 10mM acetic acid. The percentage of ACN in the mobile-phase linearly increased to 95% for 5 minutes and was held at 95% ACN for 2.5 minutes. After a total of 7.5 minutes the percentage of ACN linearly decreased for 0.5 minutes to the initial mobile-phase composition and remained there to the end of the run for a total of 11 minutes. Flow-rate: 0.3 ml/min. Ionization: positive ionization mode (PI). 4. METHOD PERFORMANCE The recovery and ion suppression of the SPE method were studied by an experimental set-up using the following samples, in triplicates: Non-spiked wastewater (Non-Spiked), Wastewater spiked prior to extraction (Pre-Extr), Wastewater spiked after extraction in the reconstitution step (Post-Extr), and Spiking solution (Sp-Sol) (20). The recovery was calculated from the “apparent” analyte concentration of samples spiked prior to and after extraction, using equation (2): Recovery = (CPre-Extr-CNon-Spiked)/(CPost-Extr-CNon-Spiked) x 100 (2) where C denotes the “apparent concentration”. Since the samples already contained a number of analytes, the native contribution to the “apparent concentration” of spiked samples was subtracted. In the case of group 1 analytes, the deuterated analogues were used as spikes. Ion suppression was calculated using the equation (3): Ion suppression (%) = (1-(CPost-Extr-CNon-Spiked)/(CSp-Sol)) x 100 (3) 32 33