Chloride determination
Comparison and improvement of different methods
Supervisor Quaker
Supervisor UvA
Produced by
Date
:
:
:
:
Dr. J.M. van der Veer
Dr. W.T. Kok
Dennis Drost
June 2012
Bachelor project 3rd year
Chloride Determination
1 Abstract
This research is focused on comparing data from different methods executed on different locations
concerning chloride determination. The goal of this research is to find what influences the analysis
of Quaker Chemical B.V. products and to search for a way to filter out/compensate for these
matrix effects. This is done by comparing previous results with new data. Different methods like
titration, ion chromatography and X-ray fluorescence are compared to give a clear picture about
what influences the different methods and how they can be improved. In the end for both titration
and ion chromatography raw materials are found that “act as if they are chloride”, and different
methods and sample preparation methods are proposed to guarantee a better chloride
determination.
1.1
Summary
Quaker Chemical B.V. is a worldwide leader in industrial lubricants. Among others they produce
lubricants for metalworking and tube & pipe industries. If these lubricants contain high
concentrations of chloride and other salts, the steel products made by those industries will be of
low quality or not usable at all because of corrosion. Many maintenance tests are carried out to
monitor the conditions of the emulsions. In this monitoring some tests give different readings when
performed at different locations, of with different methods. One of these is chloride determination.
The purpose of my bachelor project is to compare the different ways of determining chloride
concentrations, investigate what factors affect the measurement and to search for a way to
compensate for these matrix effects or to eliminate these effects all together.
The purpose of my bachelor project is:
 To compare the different ways of determining chloride concentrations
 To investigate the factors that affect/interfere with this measurement
 To search for a way to compensate for the matrix effects or to eliminate the effects all
together
In this research I mainly focused at titration and ion chromatography, but also looked at X-ray
fluorescence. It was found that with the titration not only the equipment can cause errors in the
measurement, but some raw materials can too. These raw materials interact the same way as
chloride in the titration and therefore are measured as chloride. Ion chromatography is initially not
the best choice for Quaker products because it’s not possible to inject organic solvents or oils into
most IC columns and most Quaker products are emulsions containing oil and organic compounds.
This can be overcome by doing a separation step prior to the injection, then ion chromatography
can be used to analyze these products. Then the problem arises that some raw materials interfere
with the chloride peak by, or coming out at, almost the same time as chloride, or chancing the
shape of the chloride peak. By chancing the column and the method, or even shifting to another
setup with different possibilities a great improvement is achieved in the analysis with ion
chromatography. Still the best results were gathered with X-ray fluorescence. This technique has
almost no hindrance from the interference that disrupts the readings with the other methods and
therefore probably can give the best results regarding the chloride concentration. At the end also a
cost-benefit analysis is done for the found methods.
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June 2012
Chloride Determination
Table of contents
1 ABSTRACT ............................................................................................. 2
1.1 SUMMARY ............................................................................................ 2
2 INTRODUCTION .................................................................................... 4
3 RESULTS ................................................................................................ 6
3.1 TITRATION ............................................................................................ 6
3.2 ION CHROMATOGRAPHY.......................................................................... 9
3.2.1 ION CHROMATOGRAPHY AT THE UNIVERSITY OF AMSTERDAM .................. 13
3.3 OTHER METHODS ................................................................................. 15
3.3.1 SCANNING ELECTRON MICROSCOPE (SEM) ............................................ 15
3.3.2 X-RAY FLUORESCENCE (XRF) ............................................................. 16
3.4 SEPARATION METHOD ........................................................................... 16
4 DISCUSSION AND CONCLUSIONS ..................................................... 19
4.1 RECOMMENDATIONS ............................................................................ 21
5 REFERENCES ...................................................................................... 23
6 ATTACHMENTS................................................................................... 24
6.1
6.2
6.3
6.4
6.5
6.6
SOLID PHASE EXTRAXTION SEPARATION METHOD ..................................... 24
TITRATION METHOD AND SETTINGS ......................................................... 24
PROJECT OUTLINE ................................................................................ 26
NAOH ELUENS CONCENTRATION SEARCH ................................................ 27
CHLORIDE TITRATION IN FRANCE ........................................................... 28
INTERNAL (UNPUBLISHED) DATA ............................................................ 29
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June 2012
Chloride Determination
2
Introduction
Quaker Chemical Corporation is a leading global provider of industrial lubricants, hydraulic fluids,
drilling fluids and metalworking fluids. They provide approximately 350 different process fluids
and associated services to a wide range of industries including steel, aluminum, automobile,
mining, aerospace, tube and pipe coatings and building materials. Quakers headquarters are located
in Conshohocken, Pennsylvania. Since 1962 the European headquarters are based in Uithoorn, the
Netherlands and from 1963 it has worldwide offices in England, Italy, Australia, Japan, Spain,
South Africa, Mexico and Canada.
Many of the metal working products are emulsifiables. They consist of a lot of different, typically
technical-grade, raw materials. These emulsions are offered as a concentrate to the customer, and
mixed on site with water up to volumes between 1 and 100 m3. The water, used to emulsify these
concentrates, is often not de-mineralized water, but on site available ground-, river-, or drinking
water. This water is often a source of pollution in the emulsions. To ensure the quality and
functioning of the emulsions for the long period of which they are used over (often several years),
various properties of the emulsions are monitored. Think of daily pH control, weekly microbe tests
and monthly difficult microbe tests and more extensive analysis including chloride determination.
Various techniques are available to determine the chloride concentration, which vary from
gravimetric and potentiometric methods like titration, to high-tech methods as ion chromatograph,
X-ray fluorescence (XRF) or inductively coupled plasma-mass spectrometry (ICP-MS).
When chloride determination is applied to Quaker
products varying of results are found. The variance
is found between different methods, data from
previous determinations, or data from other
locations1. This often leads to unresolved debates
about the conditions of the products and makes the
exact condition of the product unknown, which
can lead to improper maintenance with potentially
adverse consequences for the customer, as can be
seen in figure 1. These consequences can be very
serious, regarding the replacements of entire
systems, corroded or damaged machinery and
claims addressed to Quaker.
Figure 1 Example of corrosion on costumer products
Chloride determination has been an issue for quite
some time at Quaker 1. Most of the time problems arise from differences between chloride
concentrations measured by a costumer (who often not discloses its analytical methods), the
analytical department at Quaker, and even between methods here2. There is no problem in
analyzing transparent, low content samples with the Marcherey-Nagel equipment (photometric
water analysis)3, Most Quaker products though are non-transparent emulsions, so this method does
not work here. The most used method to determine the chloride concentration at Quaker is titration
with AgNO3,. This because it is a very simple technique that can easily be done at the small labs,
available at the fabric. It is based on the reaction of Cl- with Ag+ titration, is an old method to
determine chloride concentrations 4 and can be influenced by a lot of other components that also
react with silver.
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June 2012
Chloride Determination
Ion chromatography is also a method that is used to analyze chloride, other ions and almost any
other charged or polar molecule5, it works good on different kinds of samples and especially on
water6. This method is based on high pressure liquid chromatography (HPLC) but then with the
interaction of ions with material in the stationary phase of a column7. So it would be very suitable
to measure the chloride content of Quaker products, even though the columns for the ion
chromatograph are not suited for injecting emulsions8.
Another method that can be used to detect chloride is X-ray fluorescence. What happens:
Materials are exposed to short wavelength radiation (X- or gamma rays) to excite some of the
atoms present in the sample. When an electron in the excited atom “falls down” in to a lower
orbital, it emits a photon with the exact energy of the difference in energy of the two orbitals. This
is effect is shown in figure 2. This photon is detected and from this exact energy the element,
emitting this specific energy, can be identified and by the intensity of the photons the
concentration can be measured9 .
Figure 2 simplified mechanism of XRF
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June 2012
Chloride Determination
3 Results
In this report names of products and components of Quaker Chemical B.V. are not given, this to
protect their intellectual properties. These names are replaced by letters.
Different methods can be used to determine chloride concentrations in samples. The one most used
by Quaker is titration with AgNO3, but this method is questioned due to its repeatability and
accuracy with emulsion samples10. Other methods that are used in this research are ion
chromatography and XRF.
3.1 Titration
At Quaker, chloride determinations are carried out by quality control (QSG). There they use a
metrohm 655 dosimat with a metrohm 6.0130.100 Ag,AgCl, 3M KCl electrode, silver reference
electrode, metrohm 657 control unit and a metrohm 672 titroprocessor as titration setup and titrate
with 0.01N AgNO3. In theory this method is very suited to determine chloride concentrations11.
The results gathered at QSG are in inconsistent when repeated. This is shown in chart 1, which
shows the difference with the theoretical expected chloride value (based on the added NaCl),
normalized to the value of the NaCl standard, so the zero value is the value theoretically expected.
To a standard NaCl solution a variety of different raw materials was added to see if, and what kind
of influence they have on the titration and the found Cl- concentration. These raw materials were
also analyzed pure and mixed with industrial water containing chloride (product B). What is
striking about these results, is that it seems that most raw materials (but mostly A and B) interfere
with the titration and that the results are fluctuating a lot.
Chart 1 Titration results QSG
To see whether the titration method itself or the setup at QSG was the source of the inconsistent
results, a new titration setup was build using a metrohm 716 DMS titrino with a metrohm
6.0130.100 (Ag, AgCl, 3M KCl) electrode, a silver reference electrode and a 0.01N AgNO3
solution. The method and settings can be found in the attachments. The results of this setup are
shown in chart 2. The chemicals A and B give the greatest influence on the titration. Also a lot of
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June 2012
Chloride Determination
raw materials cause multiple end points on the titration. Again material A and material B cause this
most of the time, but others like material C and D have multiple end points also , while NaCl on
the new titration setup always has one endpoint. The titration setup at QSG can also give multiple
endpoints even for NaCl standard solutions.
Chart 2 Titration results own setup
To compensate for these matrix effects the standard addition method was performed. With the
standard addition method known amounts of the analyte is added to a sample of unknown
analyte. When the results are put in a graph a line can be plotted trough these points and where this
line goes through the x-axis (y=0) the absolute value of that point is the concentration of the
sample 12 . For this test a product of Quaker was chosen which gave the greatest fluctuations in
previous analysis (product A). This product was tested as a 10% emulsion, which is close to its
working parameters.
Chart 3 Results of standard addition method with titration
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June 2012
Chloride Determination
In chart 3the results of the SA method on product A is shown. The first end point (EP) of the
titration is clearly not the one caused by chloride, as it does not increase when more NaCl is added
to the sample.
In an attempt to get better results a separation was performed using HNO3, about which more
information can be found in paragraph 3.4. HNO3 was used because again the SA method was used
to see if there was less interference. This is true when the 0 value is close to the calculated value,
and if the now found value is close to the original value of the whole emulsion.
As can be seen in chart 4 the found value is quite low, but can be caused by two reasons. One; by
adding the acid the water layer is diluted because the acid itself is also diluted in water and
second; the 0 measurement is a lot lower than the rest of the line, so it can be a deviation. The
chloride concentrations of product A ranges from 268-485 ppm when analyzed at QSG and with
the new setup lying around 471 ppm, both with two endpoints. The difference is further explained
in the conclusion but can be due to the equipment used at QSG
standaard additie methode
80
y = 983.64x + 2.6007
R² = 0.9953
70
60
ppm Cl
50
EP1
Linear (EP1)
40
30
20
10
0
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
concentratie Cl toegevoegd (mg/ml)
Chart 4 SA method with titration on water layer
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June 2012
Chloride Determination
3.2 Ion Chromatography
Ion chromatography has been used by Quaker in the past to determine chloride concentrations13.
Then it was found that there are interfering peaks close to/ underneath the chloride peak and that
titration at the moment was an easier option to determine chloride in emulsions because IC had too
much interference1. Because ion chromatography should be very suitable to detect chloride7, this
technique is also included again to check Quaker products to see if with different methods it can be
used.
The Standard addition method was also done using the ion chromatograph. With the IC it has been
unable to do a good analysis of the water layer after the previous used separation, because it is too
acidic for the column. When trying to neutralize the water layer, as much base is needed that the
detector of the IC gets overloaded by the Na+ or other ions in these bases. When separation by salt
is done, it is found that multivalent salts work better. The salt that was used in the end was
KAl(SO4)2. The same goes for separation by salt. Here again so much salt is needed that the
detector gets overloaded, and the Cl- peak is undetectable, falls under the overloaded peak or
deformed too much.
In chart 5 the standard addition method was done on the emulsion rather than on the water layer
after a separation, because a suitable separation method was not found yet. This method gives a
higher concentration than found with the titration. With this the concentration chloride in the 10%
emulsion of product A is found 83 ppm.
product A standaard additie
160
y = 1008.6x + 16.795
R2 = 0.9987
140
120
ppm
100
80
60
40
20
0
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
concentration added Cl (m g/m l)
Chart 5 Results SA method 10% emulsion product A
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June 2012
Chloride Determination
Chart 6 and 7 are product A compared to product A spiked with different raw materials. This was
done to see if these materials affect the Cl- detection when using ion chromatography. It shows
that material F (which is 45% material C diluted in TEA/water) clearly broadens the peak and also
influences the area of the peak, making it 158 instead of 105 ppm. Material B is influencing the
detection of Cl- in almost the same way, also broadening and shortening the peak.
90 1 - vanaf 4-18 #16 [modified by Drostd]
µS
1 - Cl - 2.333
product A
2 - 3.033
3 - 3.783
1
ECD_1
4 - PO4 - 7.500
-10
35.0 2 - vanaf 4-18 #17
µS
product A 10ml spiked met 1ml 10% F
ECD_1
1 - Cl - 2.383
4 - PO4 - 7.500
2 - 3.083
3 - 3.817
2
-5.0
90 3 - vanaf 4-18 #18
µS
product A 10ml spiked met 1ml 10% G
ECD_1
1 - Cl - 2.333
5 - 7.117
- 2.933
2 - 32.650
4 - 3.683
3
6 - 8.333
-10
90 4 - vanaf 4-18 #19
µS
4
-10
0.0
product A 10ml spiked met 1ml 10% H
4 - 6.983 5 - 682 - 8.083
2 - 2.900
3 - 3.650
1.3
ECD_1
1 - Cl - 2.350
2.5
3.8
5.0
6.3
7.5
8.8
6 - 10.283
10.0
11.3
min
12.5
13.8
15.0
Chart 6 Product A spiked with material F, G and H
90 1 - vanaf 4-18 #20
µS
product A
ECD_1
1 - Cl - 2.383
4 - 6.817
2 - 3.000
3 - 3.717
1
-10
90 2 - vanaf 4-18 #21
µS
product A 10ml spiked met 1ml 10%I
ECD_1
1 - 2.467
4 - 6.700
2 - 2.967
3 - 3.667
2
5 - 10.517
-10
50.0 3 - vanaf 4-18 #22
µS
product A 10ml spiked met 1ml 10% B
ECD_1
1 - Cl - 2.367
5 - 6.567
4 - 6.067
3
-5.0
0.0
2 - 2.867
3 - Br - 3.533
min
1.3
2.5
3.8
5.0
6.3
7.5
8.8
10.0
11.3
12.5
13.8
15.0
Chart 7 Product A spiked with material I and B
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June 2012
Chloride Determination
Because of the nice results gained at the University of Amsterdam (see chapter 3.2.1) the NaOH
eluens used there was also tried at Quaker. Because of the different column, different
concentrations where tried to see what concentrations worked best at Quaker. 15mM NaOH gave
the best results as can be seen in the attachments (chapter 6.4), chart 9 shows the results of product
A run with this eluens.
Chart 8 Product A and C compared with product C spiked with material F. Red arrow is the chloride peak, the blue arrow is the peak
suspected from material I and the green arrow is probably from material F.
Chart 9 Product A run with the final eluens (15 mM NaOH)
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June 2012
Chloride Determination
Chart 10 shows the spectrum of product A with one of the best separations of the chloride peak
and the peak from material I. When a calibration line is made it is found that this sample contains
328 ppm chloride, but due to its bad shape and low plate of around 800 or even under 500
sometimes while at the University of Amsterdam (UvA) a plate number of over 3000 is average.
The average chloride concentration found with ion chromatography is 272ppm but it varies a lot
depending on the peak of other components that come out of the column at the same time as
chloride most of the time.
29.5 15 mM NaOH eluens SPE #36 [modified by Drostd]
µS
PA concentraat 10x verdunt
ECD_1
2 - 2.423
25.0
3 - Cl - 2.570
20.0
15.0
10.0
5.0
1 - 2.173
4 - NO3 - 5.757
0.0
-3.8
0.26
min
1.00
2.00
3.00
4.00
5.00
6.00
7.00
7.85
Chart 10 Product A, only spectra where the peak underneath the chloride peak was seen as a separate peak
Product B (shown in chart 11) is industrial water and is mostly used to compare the chloride peak.
This because it is closer to the real products than a standard solution, but still is clean enough to
get good peaks.
45.0 vanaf 4-18 #25
µS
produc B
ECD_1
1 - Cl - 1.983
30.0
20.0
10.0
3 - 6.667
2 - 3.300
4 - 682 - 7.950
-5.0
0.0
min
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
Chart 11 Ion chromatograph product B
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June 2012
Chloride Determination
3.2.1 Ion chromatography at the University of Amsterdam
At Quaker the ion chromatograph had been out of use for more than a year and also the used
columns are over date. To see if this gave additional problems detecting the right amount of
chloride at the UvA the ICS-1000 was used with a ionpac AS-11 column and AG-11 guard
column, the IC was also equipped with a ASRS 300 4mm chemical suppressor. The result is
shown in chart 12. Because here more peaks are shown before chloride than at Quaker and because
the chloride peak at Quaker might have another peak underneath it. The molecules that are
underneath the chloride peak can interact at almost the same way as chloride and therefore come
out at the same time. To separate these, the eluens generator can give a better separation at the start
of the chromatogram, where chloride comes out. Examples of this can be seen in chart 12 and 13
where the chloride peak is sharper when compared with results gathered at Quaker.
4.00 40mM NaOH ionpac AS20 #2
µS
Product A SPE
ECD_1
4 - Cl - 2.600
3.00
2.00
2 - F - 2.050
1.00
5 - NO3 - 3.100
3 - 2.220
7 - 4.760
6 - 3.553
1 - 1.617
0.00
-1.00
-2.00
-3.00
0.48
min
1.00
2.00
3.00
4.00
5.00
6.00
7.13
Chart 12 Chromatograph product A measured at the UvA
12.0 40mM NaOH ionpac AS20 #3
µS
PA & I SPE
4 - Cl - 2.607
7.5
5.0
6 - 3.587
2.5
2 - F - 2.060
3 - 2.230
0.0
-4.0
0.0
5 - NO3 - 3.110
1 - 0.453
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
Chart 13 Product A spiked with I measured at the UvA
In the last period of this research there also was access to an ion chromatograph with an eluent
generator and herewith the ability to create a gradient. This was the DX500 consisting of a GS50
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June 2012
8.0
8.5
Chloride Determination
gradient pump, CD25 conductivity detector, AS50 chromatography compartment and the AS50
auto sampler. The main use of this was to create an even better separation at the beginning of the
run and flush out everything at the end without having to wait more than a hour for the last parts to
come out. The eluens generator used a thermo scientific eluent generator cartridge EGCIII KOH to
generate the gradient out of demi water.
As can be seen in chart 14 the first part of the chromatogram is separated very well and after the
chloride peak the rest comes out fast.
Chart 14 Standard solution measured with gradient
The measurement of product A itself failed. There was no time to run it again, but in chart 15 can
be seen that the separation of material F is a lot better in comparison with a normal eluens.
Chart 15 Product A spiked with material B, F and I measured with eluens generator
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June 2012
Chloride Determination
3.3 Other methods
3.3.1 Scanning electron microscope (SEM)
The electron microscope is used to analyze different salts created by reacting both material A and
NaCl with AgNO3. The created precipitation was dried to a salt and analyzed. For the other
materials of interest for analysis with the SEM I was unable to get a salt from the precipitation that
meets the SEM’s requirements, being totally dry and being big enough grains.
Material A is an organic sodium salt containing a sulfur atom, which is bound to the sodium.
Chloride is practically not present in this salt, but sodium, sulfur and carbon are present in high
concentrations as can be seen in chart 16. Recognizable parts are that N:O ≈ 1:3 and N:Ag ≈ 1:1
(in %Atomic mass) which is probably from AgNO3. The fact that chloride is not seen means that,
while this material gives a reaction like chloride in the titration, another reaction is taking place.
This can be sulfate reacting with silver, because the sulfate is, like the chloride, charged negative
and in salt form bound to sodium.
In the analysis of the reaction product of NaCl and AgNO3 it was found that this reaction occurs
clean, we found no by-products. NaNO3 is very soluble in water, so it is probably washed away
before drying the precipitation. Again N:O ≈ 1:3 and N:Na ≈ 1:1, also Ag:Cl ≈ 1:1 as found in
chart 17
Chart 16 SEM spectrum reaction product of material A with AgNO3
Chart 17 SEM spectrum AgCl
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June 2012
Chloride Determination
3.3.2 X-ray fluorescence (XRF)
The XRF was used as a reference method to determine the chloride concentration in different
samples. XRF is a very good way to determine the precise amount of elements present in samples.
The zero value due to the silver source, which has a line at the chloride place, is around 5900 and
can differ 2% as was found doing the measurements.
Table 1 shows the results for different samples gathered with XRF.
XRF
700
y = 0.0896x - 531.6
R² = 0.9992
600
500
400
300
200
100
0
5500
7500
9500
11500
13500
Chart 18 Calibration curve XRF
Sample
Material A
Material B
Product A
Product B
Product C
ppm
534.08
2477.49
221.50
72.33
94.09
Table 1 Results XRF
3.4 Separation method
Because most of the products tested are emulsions, a separation of the oil and water part of the
emulsion is desirable, assuming that the chloride stays in the water layer and most of the
interfering components stay in the oil part. To check for each method how much of the oil was
separated a dry weight balance was used and all separations where tried on product A.
Because of the fact that the emulsions used by metalworking are micro emulsions (particle size <
200nm) centrifugation is not an option because the particles stay in emulsion. When centrifugation
is tested and the top layer is measured in the dry weight balance 4.18% stays behind, which is very
close to the initial emulsion concentration of 10% especially considering that the concentrates
itself also contains water. The emulsifiers used by Quaker are a mix of ionic and non-ionic
emulsifiers. This means that they can be destabilized by chancing their charge, to neutral or to
having a charge. This can be done by adding special polymers designed to destabilize these
emulsions. The problem is that they all have chloride as an ion, this means that using these
polymers will make the chloride determination after separating a lot harder because now there is
also chloride in it from the separation polymer. Another possibility to separate the emulsion is to
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June 2012
Chloride Determination
change the charge of the emulsifiers by using strong acid or multivalent salt. Using HNO3 good
results were achieved in separating product A. By titration one of the multiple endpoints
disappeared, so some of the interfering substances are gone.
But when an emulsion is split with acid, the resulting water layer cannot be analyzed with ion
chromatography. This is due to the pH of about 0 or lower of the water layer while most columns
can handle between 1 and 12. When trying to neutralize the water layer as much base is needed
that the detector gets overloaded (almost all bases contain salt). If the sample is diluted just enough
so the detector does not get overloaded, the peak of chloride is so small it is not visible anymore.
When using salt to separate the emulsion the same effect arises, the detector gets overloaded.
In the search for a good separation method within the parameters of the ion chromatograph it was
found that hexane and 1-butanol can improve the separation. To test this and look for the best way
to prepare the samples for the IC 5, different samples were made, all with different separation
methods.
According to table 2, sample 1 and 2 are the best ways to separate the emulsion. Sample 2 looked
better separated visually and both looked almost the same on the ion chromatograph (chart 19). So
a combination of the two was used, namely: 10ml sample with 5ml KAl(SO4)2, ½ drop of HNO3
(68%) with 4ml hexane and 5ml 1-butanol.
Sample nr
Emulsion
KAl(SO4)2
1
10 ml
3 ml
HNO3 68%
.5 drop
2
10 ml
5 ml
.5 drop
3
10 ml
2 ml
1ml
4
10 ml
2 ml
1ml
5
8 ml
8 ml
hexane
1-butanol
3 ml
3 ml
1 ml
5 ml
emulsion%
6
2.2
6
3.11
3
5 ml
3.14
3
4 ml
3.09
5
5 ml
1 drop
pH of water layer
1.14
Table 2 Content and resulting separation and pH of the different tubes
0.60 1 - VANAF 4-18 #60 [modified by ARGLab]
µS
reageerbuis 13
ECD_1
1 - Cl - 1.783
1
-0.50
1.00 2 - VANAF 4-18 #61 [modified by ARGLab]
µS
reageerbuis 14
ECD_1
1 - Cl - 1.800
2
-0.60
1.00 3 - VANAF 4-18 #62 [modified by ARGLab]
µS
reageerbuis 15
ECD_1
1 - 1.817
2 - Cl - 2.033
3
-0.60
0.80 4 - VANAF 4-18 #63 [modified by ARGLab]
µS
reageerbuis 16
ECD_1
2 - Cl - 2.017
1 - F - 1.467
4
-0.60
0.60 5 - VANAF 4-18 #64 [modified by ARGLab]
µS
reageerbuis 17
ECD_1
1 - Cl - 1.800
5
-0.50
0.36
min
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
2.75
3.08
Chart 19 IC spectra of tubes 1 to 5 focused on the chloride peak
- 17 -
June 2012
Chloride Determination
After some time it appears that the recovery of this method was not very good. The main reason
being, that the water mixes with the 1-butanol. This causes a dilution factor that is not included in
the calculations and so generating wrong data. Because the exact mixture is unknown and also the
percentage of the chloride that stays in the water instead of in the hexane or 1-butanol is unknown,
this method was found to be under expectations.
The most effective method that has been found to separate the emulsion is using a strata C-18 SPE
column. The exact method can be found in the attachments. The separation is based on the
principle that the oil has more interaction with the column than water and therefore comes out of
the column later. Not having to add substances detectable by the ion chromatograph is one of the
biggest advantages of this method. Another is that one does not (if executed correctly) dilute a
sample in the separation process. The recovery is found to be around 95% as can be calculated
from the data available in table 3 and can be seen by the almost identical peaks in chart 20. This
can be both lower and higher though, depending on how much the column is flushed with sample
before the sample is collected; the more the higher the recovery. The emulsion percentage of this
method is found to be less than 1%.
1 - 15 MM NAOH ELUENS SPE #13
2 - 15 MM NAOH ELUENS SPE #14
3 - 15 MM NAOH ELUENS SPE #15
9.7 4 - 15 MM NAOH ELUENS SPE #16
µS
NaCl 38.279gr/250ml zonder SPE 10x verdunt
NaCl 38.279gr/250ml zonder SPE 10x verdunt
NaCl 38.279gr/250ml met SPE 10x verdunt
NaCl 38.279gr/250ml met SPE 10x verdunt
ECD_1
ECD_1
ECD_1
ECD_1
1 - Cl - 2.650
8.0
6.0
4.0
2.0
1
2
3
4
min
-0.6
0.45
1.00
1.50
2.00
2.50
3.00
3.72
Chart 20 Chloride peak before and after SPE method
Sample No.
Sample Name
Ret.Time
Area
(min)
Height
(µS*min)
Amount (ppm)
13 NaCl 38.279gr/250ml zonder SPE 10x verdunt
2.617
16.132
81.834
142.23
14 NaCl 38.279gr/250ml zonder SPE 10x verdunt
2.600
16.376
87.745
144.23
15 NaCl 38.279gr/250ml met SPE 10x verdunt
2.617
15.968
89.473
140.90
16 NaCl 38.279gr/250ml met SPE 10x verdunt
2.650
16.954
92.862
148.97
2.621
16.358
87.979
144.08
Average:
Table 3: Data belonging to chart 20, chloride peak before and after SPE method
- 18 -
June 2012
Chloride Determination
4 Discussion and Conclusions
The now used titration by Quaker at QSG gives very fluctuating results which can be seen in chart
1. This is probably not just due to the method itself, but also due the way it’s used and the age of
the equipment. When titration is done in another
setup, or in another place the results constantly give
more than one endpoint (EP). The multiple endpoint
problem is smaller as can be seen in chart 2 and in the
titration results at France in the attachments. One of
the problems can be the auto sampler that is used,
when the electrodes are still dripping from the
cleaning the auto sampler already starts turning. This
can be seen by the drips of water that are between the
samples (figure 3). This causes some of the old
samples to pollute the next samples. This can be one
of the reasons for the multiple endpoints gathered to.
Figure 3 drop of sample on the auto sampler
Also it is possible that some of the raw materials can
react with the silver surface of the reference
electrode, and this needs to be sanded away.
Even so: Executed perfectly titration is not a very good method to determine the chloride content
in Quaker products. Most Quaker products contain a lot of sodium salts containing sulfur groups,
like material A and B. These, if diluted, charged sulfur groups react with silver in the same way as
chloride does in the titration reaction and therefore is seen as chloride in the determination. This
effect can be seen in chart 2 looking at material A and B. These values are higher than expected,
based on the added chloride content. A small part of this can be due to the chloride present in the
raw material itself (material B holds a maximum of 2% chloride) but mostly it is due to the
reaction of sulfur with silver. This is supported by the data gathered with the electron microscope,
which shows that if material A reacts with AgNO3, a different reaction product arises then in the
reaction of sodium chloride with AgNO3. By looking at the ratio of the different atoms, silver
chloride is most probably the reaction product of the titration of NaCl with AgNO3 as expected.
But when material A reacts with AgNO3 the product is probably not AgCl but AgS- material A
which can be concluded by the ratios of the atoms present in the sample.
Theoretically ion chromatography is a very good way to analyze samples for chloride. The
problem with Quaker products is their complexity. Most of the products consist of over 20
different raw materials and intermediates of which some are salts. These materials and especially
the salts can interfere with the reading. They can come out at almost the same time as chloride or
change/shift the chloride peak so that it would be harder to get a clear measurement. Examples of
raw materials changing/interfering with the peak of chloride can be seen in chart 6 and chart 7.
Here it is shown that material B and F influence the height and the width of the chloride peak a lot.
None of the peaks shown in these graphs are nice symmetrical peaks, which suggest that in all
samples something else comes out of the column at almost the same time as chloride. This was
confirmed when additional measurements were done at the UvA as can be seen in chart 12. It
shows two clear peaks before the chloride peak which are not (clear) shown on the measurements
at Quaker. The measurements at the UvA were done to check if the bad measurements could be
due to the long time the equipment was not used and the fact that the columns are over date. The
- 19 -
June 2012
Chloride Determination
data collected at the UvA shows that another method, equipment and column can greatly improve
the analysis.
Another reason why ion chromatography is harder for Quaker products is that most IC columns
cannot handle organic solvents or oils, and almost all Quaker products are emulsions. The
separation method used at the titration included adding a lot of salt or strong acid. Both made it
impossible to use these samples in the ion chromatograph because of the pH range of the column,
or that the salt overloads the detector so the desired peaks cannot be seen. In the search for a
separation method suitable for IC analysis different combinations of KAl(SO4)2, HNO3, hexane
and 1-butanol are used to find a way to keep the pH in the range of the column, so the detector is
not overloading but still giving a good separation. In table 2 the content of the different tubes is
shown, and their level of separation and pH. Together with their IC spectra (chart 19) it was
observed that tube 1 and 2 gave the best results, so a combination of these two was chosen namely:
10ml sample with 5ml KAl(SO4)2, ½ drop of (about 0.05 ml)HNO3 (68%) with 4ml hexane and
5ml 1-butanol. It was found that this method had a very poor recovery because of 1-butanol
mixing with water and therefore diluting the water layer, and even worse introducing organic
solvents to the ion chromatograph. After this solid phase extraction (SPE) a convenient way to
separate the emulsion was found. This was done by using a C-18 SPE column. This method was
found the best sample preparation for ion chromatography, because no particles detectible by the
IC were added. The recovery is close to 100% because chloride does not interact with the material
in the column and the sample is almost not diluted in the process.
X-ray fluorescence is the technique found to be the least affected by the matrix of the emulsion.
One of the problems is that the silver radiation source has energy lines falling on the same place as
the chloride lines. This makes the chloride peak change around 1%, but this is far less than the
accuracy of the other methods due to matrix effects.
In table 4 the measurements considering products A and C with different techniques are
summarized. It can be concluded that titration is not suited to determine the chloride concentration
for Quaker products, because of the interference caused by different raw materials 2. These
materials, mostly sulfur containing, react the same way with silver as chloride does and so are seen
as chloride. Ion chromatography combined with the SPE separation method would be very
suitable for the analysis of Quaker products, however the actual method needs to be studied
further, as can be found in my recommendation. With the current methods there are other materials
coming out of the column at the same time as chloride, and therefore it is difficult to get a good
reading of the chloride concentration. Even with those other materials coming out at the same time
though, the interference is smaller as can be reasoned from the lower concentration, found with ion
chromatography than by titration. Still the best method tested was X-ray fluorescence, because
there is no interference of other materials and the reading only changes due to the silver source
which radiates at the chloride line to.
Method
Titration QSG
Titration new setup
Ion chromatography
x-ray fluorescence
Chloride concentration product A
268-485ppm
471 ppm
272 ppm
221.5 ppm
Chloride concentration product C
114 ppm
112.8 ppm
72.3 ppm
Table 4 chloride concentrations measured with different techniques
- 20 -
June 2012
Chloride Determination
It is hard to compare the found chloride concentrations to theoretical data, because there is not
much known about this in most raw materials. So the calculations that can be made only contain
data about 25% of the used raw materials and therefore give results that are a lot lower than the
actual measured concentrations.
4.1 Recommendations
It is recommended to change the standard chloride measuring method to ion chromatography or XRay fluorescence. While ion chromatography needs more research to find the best method for
analyzing emulsions, the method itself is very suited to find not only chloride but also most other
ions that are now measured with other equipment (think of Marcherey-Nagel or reflectoquant).
This method however may need some additional investments concerning columns and a leaking
chemical suppressor. X-Ray fluorescence is the best option to detect chloride without matrix
effects, also it can be used to detect some other of the elements that are now checked for in other
tests, but it can’t detect (directly) the ions consisting of more than one atom, molecules. Another
drawback of this method is that there is only one XRF available at Quaker Uithoorn and it is most
of the time used by the steel department.
Concerning the now used method the recommendation is to check the titration setup of QSG, if it
still gives good and repeatable results, based on the fluctuating data gathered there (chart 1). If
used on a clean and good working setup titration it can still be used to give a good estimation for
most Quaker products, but products containing raw materials that have (charged) sulfur groups
will give higher values because of these raw materials.
loon chemist per uur
Time analysis (hour)
Analyses per month
Material cost per analysis
Cost equipment
Depreciate time (year)
Material/expenses p/y
100
IC Quaker
0.25
50
1.50
10
2000.00
XRF
quaker
0.12
50
0.50
46000.00
10
800.00
XRF laten
doen
0.00
50
70.00
0.00
1
0.00
titratie
Quaker
0.10
50
0.10
0.00
10
0.00
ICS-1600
0.25
50
0.50
35000.00
10
2000.00
comment
Cost per analysis
Cost per year
ICS-2100
0.10
50
0.50
55000.00
10
2500.00
gradient
autosampler
29.83
4,150.00
21.50
6,300.00
70.00
42,000.00
10.10
560.00
34.67
7,050.00
23.83
8,800.00
Table 5 Cost of different analysis
Based on table 5 and all other data gathered in this report switching to ion chromatography for
standard emulsion analysis is a affordable option. To do this for example the ICS-2100 will be a
suited system because it comes with the possibility of a gradient due to the eluent generator and the
auto sampler makes the time of the analysis shorter which makes it cheaper per sample. Personally
I recommend IC over XRF, because IC has the potential to do a lot of standard analysis done now
with different methods all at once.
- 21 -
June 2012
Chloride Determination
To make ion chromatography the new method for (standard) analysis of emulsions, or other
samples at Quaker, additional research needs to be done to the separation method so that no oil or
organic solvents will be injected in the column. When a new ion chromatography is bought,
research is needed to find the best columns, gradient and other specifications to get the best
separation of the peaks from the analyte and other compounds.
- 22 -
June 2012
Chloride Determination
5 References
(1) Merkenstein, W. V. Comparison of chloride determination methods. can be found in the
attachements 2006.
(2) Smit, E. Chloride content analyses. can be found in the attachements 2006.
(3) Schneider, R. Photometric water analysis. Suitability for companies self control;
Photometrische Wasseranalytik. Eignung von Kuevettentesten zur betrieblichen
Eigenkontrolle. GIT 2001, 45, 630-632.
(4) Zall, D. M.; Fisher, D.; Garner, M. Q. Photometric determination of chlorides in water. Anal.
Chem. 1956, 28, 1665-1668.
(5) Hern, J.; Rutherford, G.; Vanloon, G. Determination of chloride, nitrate, sulphate and total
sulphur in environmental samples by single-column ion chromatography. Talanta 1983, 30,
677-682.
(6) MUSMECI, L.; BECCALONI, E.; CHIRICO, M. Determination of Chloride in the Leachates
of Stabilized Waste by Ion Chromatography and by a Volumetric Method - Analysis and
Comparison. J. Chromatogr. A 1995, 706, 321-325.
(7) Haddad, P. R.; Jackson, P. E. In Ion chromatography: principles and applications; Elsevier
Science: 1990; Vol. 46.
(8) Weiss, J. Handbook of ion chromatography, 2 Volumes. Recherche 2004, 67, 02.
(9) Beckhoff, B.; Langhoff, N.; Kanngiefer, B.; Wedell, R.; Wolff, H. In Handbook of practical Xray fluorescence analysis; Springer Verlag: 2006; .
(10) Beau, J. Chloride titration in emulsions. can be found in the attachements 2011.
(11) ZANCATO, M.; PIETROGRANDE, A.; MACCA, C. Sequential Determination of Sulfur and
Chlorine in Organic-Compounds by Potentiometric Titration of Sulfate and Chloride with an
Automatic Titrator. Ann. Chim. 1990, 80, 445-451.
(12) Saxberg, B. E. H.; Kowalski, B. R. Generalized standard addition method. Anal. Chem. 1979,
51, 1031-1038.
(13) Butter, I. Determinatino of chloride and sulphate concentration in two products. can be found
in the attachements 2006.
- 23 -
June 2012
Chloride Determination
6 Attachments
6.1 Solid Phase Extraxtion separation method





Using a C-18 strata SPE column under -10kPa vacuum, activate the column by flushing
two bed volumes of MeOH.
To clean the column add a minimum of four bed volumes H2O, this is important, otherwise
there will be chloride from the column in your monster!
Add at least 2 bed volumes of sample, if wanting to dilute it before injection in the ion
chromatograph, add the diluted sample to the SPE this gives better results.
Wait until at least one bed volume of sample is absorbed by the column before collecting
the actual sample, this to prevent diluting the sample with the H2O present in the column
from the cleaning.
The collected sample can directly be injected in the ion chromatograph without a filter.
6.2 Titration method and settings
- 24 -
June 2012
Chloride Determination
- 25 -
June 2012
Chloride Determination
6.3 Project outline
- 26 -
June 2012
Chloride Determination
6.4 NaOH eluens concentration search
16.0 15 mM NaOH eluens SPE #2
µS
standaard zonder spe 3mMNaOH
ECD_1
1 - 2.717
2 - 4.150
12.5
10.0
7.5
3 - 7.017
4 - 8.650
5.0
2.5
0.0
-2.0
0.0
min
2.5
5.0
7.5
10.0
20.0 15 mM NaOH eluens SPE #3
µS
2 - 2.767
1 - 1.850
12.5
15.0
17.5
20.0
22.5
25.0
27.5
standaard zonder spe 10mMNaOH
30.0
ECD_1
17.5
15.0
12.5
10.0
3 - Br - 4.600
4 - NO3 - 5.633
7.5
5.0
6 - 25.617
2.5
5 - 10.450
-2.0
0.0
min
2.5
5.0
7.5
10.0
25.0 15 mM NaOH eluens SPE #4
µS
2 - 2.300
12.5
15.0
17.5
20.0
22.5
25.0
27.5
standaard zonder spe 15mMNaOH
30.0
ECD_1
1 - F - 1.617
20.0
15.0
3 - 3.667
4 - Br - 4.433
10.0
5 - 13.067
5.0
0.0
-5.0
0.0
min
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
- 27 -
22.5
25.0
27.5
30.0
June 2012
Chloride Determination
6.5 Chloride titration in France
- 28 -
June 2012
Chloride Determination
6.6 Internal (unpublished) data




Chloride content method
Comparison of chloride determinations combined
Chloride 40032-11 and 041208-05
Determination of chloride and sulfate concentration in two products
- 29 -
June 2012
Chloride Determination
Report to
:
Andre Hendriksen
Reported by
:
Julie Beau
Date of report
:
19 December, 2011
Account
:
Internal / Klant
Subject
:
Reference
:
EU-MG 2011-1527
Object
:
Chloride titration in emulsions
Introduction
It was requested to MWCSLNL to perform two chloride titrations on two products (041837-01 and
043040-01) theoretically containing 170ppm chloride for Klant.
Materials and Methods
Materials
043040-01
041837-01
Method
The analyses are performed according to standard QTN methods.
- 30 -
June 2012
Chloride Determination
Results
First tests have been performed with the standard method (equipment used at QSG) using 10.00g
of a 5% emulsion in demineralised water (meaning we should find a result around 8.5 ppm):
EP1 (ppm)
EP2 (ppm)
Average value
(ppm)
043040-01
11
22
041837-01
2
5
It has been asked to QSG how do they deal with two EPs and we have been told that they usually
calculate the average.
Since the results were not really coherent, we have considered that it might be due to the fact that
the concentration was too low. Thus, new titrations were performed with 20.00g of 10% emulsions
(meaning we should find a result around 17 ppm):
EP1 (ppm)
EP2 (ppm)
Average value
(ppm)
5% 043040-01 in
21
30
25.5
demi
5% 041837-01 in
13
18
15.5
demi
Generally speaking, we can say that between those two measurements, the tendency is that the
chloride content in 041837-01 is lower than in 043040-01 but the values are not doubled compared to
the first values which could have been expected.
It has been decided to perform 3 more times the same titration with the same 10% emulsion.
EP1 (ppm)
EP2 (ppm)
Average value
(ppm)
21
30
25.5
19
24
21.5
10% 043040-01 in
demi
27
44
35.5
11
21
16
13
18
15.5
7
11
9
10% 041837-01 in
demi
13
26
18
12
31
21.5
- 31 -
June 2012
Chloride Determination
There is no consistency in the results. The curves on the printed tickets do not have the same profile
and the existence of two bending points is questionable. It seems that the titration is performed
correctly but it might be that the detection equipment of the turning point is too sensitive and is set to
stop after the second detected point.
Example:
In this case, the equipment detects a stable period that is too short to be a
‘real’ bending point. In this particular case, it would be suggested to only
consider the second value given/calculated by the measuring device. This has
been confirmed when known chloride salts samples have been titrated.
Considering this reasoning, the equipment gives the following results for the
mentioned samples:
calculated value (ppm)
measured value (ppm)
0
0.2 (only one EP)
10
7.6 (only one EP)
50
46.7
100
96.8
Unfortunately, it is not that clear and it can happen that we have two distinct bends or a linear line
where the equipment detects already two stable periods and stops the measurement.
In order to determine the chloride content of the samples for Klant, measurements have been
performed with the XRF equipment from BRUKER but at low concentration (<100ppm) the
measurements are not accurate enough.
Ion chromatography has also been performed but this method is more adapted to water samples. It
would require a complicated preparation of emulsion samples.
Conclusions
With the standard method, the titration is done correctly but we have to be careful with the automatic
result values that are given. The reading of the curve can help but when not possible, the values can be
uncertain.
Even though the performed tests were not very conclusive, the use of a handheld XRF might not be to
exclude for chlorine content determination. The inaccuracy of the results is partly due to the fact that
the chlorine peak is merged with the rhodium peak. This might be solvable with a particular set up of
the equipment.
Ion chromatography is not suitable for emulsion samples.
In any case, a discussion should be initiated (also with QSG) on the accuracy of the results we get
with the standard method and how we can improve it to give more reliable results in our reports.
- 32 -
June 2012
Chloride Determination
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Chloride Determination
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Chloride Determination
Report to
:
J. Hooijman
Reported by :
E. Smit
Date of report
:
Account
:
Klant
Subject
:
040032-11 and 041208-05
Reference
:
EU-MG 2006-1038
Object :
Chloride content analyses
March 13, 2006
Introduction
Klant used the 040032-11 and the 041208-05. Both concentrates have been analysed by the customer
on Chloride content by titration with Silver Nitrate solution. The customer found a result of 20003000 ppm in both products. The Chloride content will be analysed by Ion-Chromatograph (IC) and by
titration with Silver Nitrate solution.
Materials and Methods
Materials:
Retain sample 040032-11 : lot# 96477.
Retain sample 041208-05 : lot# 90636.
Sample made at the lab; march 2006 (040308-07)
Methods:
Standard QTN Methods.
- 40 -
June 2012
Chloride Determination
Results
For all three concentrates the Chloride content is analysed by IC and by titration with Silver Nitrate
solution.
Description
Chloride by
IC
Chloride by
AgNO3
Results
customer
041208-05
287
040032-11
601
Sample made at lab
502
UOM
ppm
Method
P012
4265
3960
495
ppm
Z026
2000-3000
2000-3000
-
ppm
When QTN Z026 is used (titration with Ag NO3 solution), only the 040032-11 gives a reasonably low
amount of Chloride. The other two concentrates contain a copper inhibitor that reacts with the Silver
Nitrate. It is analysed before that concentrates containing this raw material show an extreme high
amount of Chloride when method Z026 is being used.
As can be seen in the table: the 040032-11 gives for both methods approximately the same amount of
Chloride. The results for the 041208-05 differ almost 4000 ppm and the results of the 040032-11
differ more than 3000 ppm.
Conclusions
The 040032-11 and the 041208-05 seem to contain around 4000 ppm Chloride when the titration with
AgNO3 solution is performed (method QTN Z026).
The 040032-11 and the 041208-05 contain 287 ppm, respectively 601 ppm when the IC is used for
analysis.
The difference between both measurements is enormous, but can be related to one raw material: the
copper corrosion inhibitor. This raw material reacts with the AgNO3.
The sample made at lab which is used as a reference shows approximately the same results for IC and
titration: 500 ppm
- 41 -
June 2012
Chloride Determination
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Chloride Determination
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