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Supplemental Data 1 2 3 Micro-scale quantitation of ten phthalate esters in water 4 samples and cosmetics by capillary liquid chromatography 5 coupled with ultraviolet detection: effective strategies to 6 reduce the production of organic waste 7 8 9 C.-H. Feng () 10 E-mail address: [email protected] 11 Tel.: 886-7-312-1101 ext 2805, fax: 886-7-321-0683 12 Full postal address: 100, Shih-Chuan 1st Road, Kaohsiung, 80708, Taiwan. 13 14 15 Results and discussion 16 Optimization of the LLE procedure 17 Comparison of average recoveries of ten phthalate esters extracted with 18 ethyl acetate, toluene and n-hexane (100, 84 and 80 %, respectively) 19 showed that ethyl acetate was the best solvent for phthalate ester 20 extraction. For extracting the 10 phthalate esters, use of ethyl acetate in a 21 single extraction of 300 L, a double extraction of 150 L, and triple 22 extraction of 100 L revealed average extraction efficiencies (percentages) 23 of 71, 90 and 100%, respectively. 1 24 25 Optimization of UAE procedure 26 Comparison of extraction efficiency at 30, 40 and 50 ℃revealed average 27 recovery percentages of 100, 99 and 94, respectively. Thus, 30 ℃was the 28 optimal temperature for phthalate ester extraction. Because of the 29 semi-volatile properties of phthalate esters, temperature increases result 30 in loss of compounds. Comparison of extraction durations of 5, 10 and 15 31 min showed that 15 min was the best extraction duration for phthalate 32 ester extraction. Extraction of ethyl acetate was compared in a single 33 extraction of 300 L, a double extraction of 150 L, and a triple 34 extraction of 100 L. The comparison showed that a double extraction 35 using 150 L ethyl acetate obtained the best extraction efficiency. 36 37 Optimization of the MAE procedure 38 For the microwave parameter, comparisons of 200, 700 and 1000 W 39 treatments in terms of effects on extraction efficiency revealed that 40 average percentages of phthalate ester extraction were 89, 100 and 94%, 41 respectively. Therefore, 700 W was the optimal microwave treatment for 42 phthalate ester extraction. For the equilibration time parameter, 43 comparisons of 3, 6 and 9 min showed that 6 min was the best 44 equilibration time for phthalate ester extraction. In terms of extraction 45 repetitions, ethyl acetate extraction was tested in a 300 L single 46 extraction, a 150 L double extraction and a 100 L triple extraction. 47 48 Optimization of the DLLME procedure 2 49 Extraction efficiencies of chloroform solvent were compared in volumes 50 of 10, 15, 20, 30, 40 and 50 L. Theoretically, extraction solvent volume 51 should correlate with the sedimented phase obtained. As expected, 52 extraction solvent volume correlated with extraction efficiency in this 53 study. Comparisons of chloroform at volumes varying from 10 to 20 L 54 showed that 20 L obtained the best extraction efficiency. However, at 55 extraction volumes exceeding 20 L, excessive dilution negated increases 56 in extraction efficiency. Next, extraction efficiency was compared in 57 various dispersive solvents, including acetone, acetonitrile and methanol. 58 When used as dispersive solvents for phthalate ester extraction, the 59 average recovery percentages of acetone, acetonitrile and methanol were 60 93, 100 and 88, respectively. Thus, acetonitrile was the best dispersive 61 solvent for DLLME. To test the effects of dispersive solvent volume, 62 extraction efficiency of acetonitrile was compared in volumes of 30, 60, 63 90, 120, 150 and 180 L. At dispersive solvent volumes smaller than 90 64 L, collecting the sedimented phase was difficult because small droplet 65 formation was unobviously. At dispersive solvent volumes exceeding 90 66 L, however, the decreased distribution coefficient of phthalate esters 67 visibly partitioned the compounds into aqueous solution. Therefore, 68 acetonitrile 90 L was the optimal dispersive solvent volume in DLLME. 69 70 Optimized DLLME-SFO procedure 71 Comparison of varying volumes (5, 10, 15, 20, 25 and 30 L) of 72 1-dodecanol solvent in terms of phthalate ester extraction efficiency in 73 DLLME-SFO showed that 20 L was the optimal volume. Next, 3 74 comparison of methanol, acetonitrile, and acetone revealed phthalate ester 75 extraction efficiencies of 86, 89, and 100%, respectively. Thus, acetone 76 was the best dispersive solvent for DLLME-SFO. Extraction efficiency of 77 acetone solvent was then compared in volumes of 30, 60, 90, 120, 150 78 and 180 L . Notably, extraction recovery decreased as acetone volume 79 increased due to the effects of dilution. At dispersive solvent volumes 80 smaller than 30 L, obtaining the solidifying phase was difficult. 81 Therefore 30 L was the optimal solvent volume when using acetone as 82 dispersive solvent in DLLME-SFO. 83 84 Optimized CPE procedure 85 Three surfactants were evaluated: Triton X-100, Triton X-114 and 86 Genapol X-080. Since the structures of Triton X-100 and Triton X-114 87 contain chromophores, high concentrations of these surfactants in the 88 CPE interfere with I.S., DprP, BBP and DBP in the chromatograms. Since 89 the structure of Genapol X-080 does notcontain chromophores; Genapol 90 X-080 was a a suitable surfactant for CPE in this study. In terms of 91 physical-chemical properties, the critical mecellar concentration (CMC) 92 of Genapol X-080 is 0.028 % (w v-1), and its cloud point is 42 ℃. Tests 93 of the phthalate ester extraction efficiency of Genapol X-080 at 94 concentrations of 1, 2, 4, 8 and 12 % (w v-1) obtained average recovery 95 percentages of 86, 95, 100, 62 and 39%, respectively. As surfactant 96 concentration increased, the partitioning of phthalate esters into micelle 97 also increased until the volume of the redundant surfactant-rich phase was 98 too large to dilute the target analytes. Therefore, the optimal Genapol 4 99 X-080 concentration was only 4 % (w v-1) in CPE. In CPE, electrolyte 100 levels may enhance extraction efficiency by altering the density of the 101 aqueous solution as well as the cloud point temperature. In this study, use 102 of NaCl (0, 1, 2, 3 and 4 % (w v-1)) as electrolyte for extracting phthalate 103 esters achieved average recovery percentages of 100, 36, 74, 40 and 34 %, 104 respectively. Therefore, NaCl should be excluded when performing CPE. 105 In temperature testing, use of NaCl at temperatures of 60, 70, 80, 90 and 106 100 ℃ obtained average recovery percentages of 100, 88, 95, 89 and 93 107 %, respectively. Although NaCl was also tested at 50 ℃, phase separation 108 was incomplete, and collecting the surfactant-rich phase was difficult. 109 Therefore, 60 ℃ was the optimal temperature for CPE extraction of 110 phthalate ester. Extraction efficiency was then compared at equilibration 111 times of 30, 45, 60, 75, 90 and 120 min. At 45-90 min, the surfactant-rich 112 phase and the aqueous phase were completely separated, and extraction 113 efficiency exceeded 94%. Hence, 45 min equilibration time was selected 114 for phthalate ester extraction. 5 Table S1. Calibration curves for inter-day and intra-day analyses of the phthalate esters Phthalate esters Linear range (μg mL-1) Inter-day Intra-day Linear equation (n=6) r2 Linear equation (n=6) r2 LOD (μg mL-1) DMP 0.5-50 y = 0.0411 x - 0.0036 0.999 y = 0.0395 x - 0.0127 0.999 0.05 DEP 0.5-50 y = 0.0319 x - 0.0150 0.998 y = 0.0308 x - 0.0203 0.997 0.02 DprP 0.5-50 y = 0.0243 x - 0.0035 0.999 y = 0.0241 x - 0.0103 0.998 0.10 BBP 0.5-50 y = 0.0230 x - 0.0129 0.998 y = 0.0236 x - 0.0190 0.997 0.10 DBP 0.5-50 y = 0.0249 x - 0.0096 0.998 y = 0.0248 x - 0.0133 0.998 0.05 DPP 0.5-50 y = 0.0187 x - 0.0086 0.998 y = 0.0192 x - 0.0141 0.998 0.06 DCHP 0.5-50 y = 0.0201 x - 0.0086 0.999 y = 0.0200 x - 0.0134 0.998 0.07 DnHP 0.5-50 y = 0.0180 x - 0.0046 0.998 y = 0.0186 x - 0.0085 0.998 0.07 DEHP 0.5-50 y = 0.0176 x - 0.0023 0.998 y = 0.0170 x - 0.0028 0.998 0.03 DOP 0.5-50 y = 0.0166 x - 0.0083 0.998 y = 0.0165 x - 0.0114 0.998 0.17 6 LLE UAE MAE DLLME DLLME-SFO CPE 120.00 Recovery (%) 100.00 80.00 60.00 40.00 20.00 0.00 PAEs Fig. S1. The recovery of a water sample by using six different techniques on the extraction of the phthalate esters (PAEs). 7 LLE UAE MAE DLLME DLLME-SFO CPE 120.00 Recovery (%) 100.00 80.00 60.00 40.00 20.00 0.00 PAEs Fig. S2. The recovery of a toner sample by using six different techniques on the extraction of the phthalate esters (PAEs). 8 LLE UAE DLLME-SFO 120.00 Recovery (%) 100.00 80.00 60.00 40.00 20.00 0.00 PAEs Fig. S3. The recovery of a emulsion sample by using three different techniques on the extraction of the phthalate esters (PAEs). 9