sd-sample article


M.P.B. Espino and J.P. Mendoza

51

SCIENCE DILIMAN  (JULY-DECEMBER 2013) 25:2, 51-66

Determination of Monochloroacetic Acid
in Swimming Pool Water
by Ion Chromatography-Conductivity Detection

Maria Pythias B. Espino*
Institute of Chemistry
University of the Philippines Diliman

Jamie P. Mendoza
Natural Science Research Institute
University of the Philippines Diliman

ABSTRACT

In this study, an analytical method involving ion chromatography with

c o n d u c t i v i t y  d e t e c t i o n  w a s  d e v e l o p e d  a n d  o p t i m i z e d  f o r  t h e

d e te r m i n a t i o n  of  m o n o c h l o r o a ce t i c a c i d  i n  s w i m m i n g  p o o l  w a te r. T h e

ion chromatographic method has a detection limit of 0.02 mg L -1 and

linear range of 0.05 to 1.0 mg L-1 with correlation coeff icient of 0.9992.

T h e  m e t h o d  i s  r e p r o d u c i b l e  w i t h  p e r c e n t  R S D  o f  0 . 0 5 2 %  ( n = 1 0 ) .  T h e

r e c o v e r y  o f  m o n o c h l o r o a c e t i c  a c i d  s p i k e d  i n  d i f f e r e n t  w a t e r  t y p e s

(bottled, tap and swimming pool water) ranged from 28 to 122%. In dilute

solutions, chloride and bromide were simultaneously analyzed along with

m o n o c h l o r o a c e t i c  a c i d  u s i n g  t h e  o p t i m i z e d  m e t h o d .  C h l o r i d e  a n d

bromide have detection limits of 0.01 to 0.05 mg L-1, respectively. The

usefulness of the ion chromatographic method was demonstrated in the

analysis of monochloroacetic acid in swimming pool water samples. In

such highly-chlorinated samples, an Ag/H cartridge was used prior to

the ion chromatographic determination so as to minimize the signal due

to chloride ion. Monochloroacetic acid was detected in concentrations

between 0.020 and 0.093 mg L-1 in three of the six swimming pool water

samples studied. The presence of monochloroacetic acid in the swimming

p o o l  w a t e r  s a m p l e s  s u g g e s t s  t h e  p o s s i b l e  o c c u r r e n c e  o f  o t h e r

disinfection by-products in these waters.

Keywords: Monochloroacetic acid, chloride, bromide, water, ion chromatography

_______________
*Corresponding Author

ISSN 0115-7809 Print / ISSN 2012-0818 Online



Determination of Monochloroacetic Acid in Swimming Pool Water

52

INTRODUCTION

Water is impor tant in sustaining life. To safeguard human and ecological health,
contaminants must be absent or kept at the minimum possible levels.  Because
water is used for human consumption, the highest quality of water should thus be
maintained.  It is common to disinfect water by ozonation or chlorination to prevent
the spread of disease. However, disinfection by-products are unintentionally
produced during water treatment.  When bromide-containing water is treated using
ozone, the potentially carcinogenic bromate may be formed (von Gunten and Hoigne
1994, WHO 2008).  Chlorination of water containing naturally-occurring organic
matter, on the other hand, results in the formation of a variety of disinfection by-
products (Liang and Singer 2003, Richardson and others 2007).  Chlorine species
such as HOCl and OCl- react with humic and fulvic substances in water to form the
regulated disinfection by-products including haloacetic acids and trihalomethanes.
Haloacetic acids are more soluble in water and are reported to be as potentially
harmful as the commonly-analyzed trihalomethanes (Nieuwenhuijsen and others
2000, Richardson and others 2007,  Plewa and others 2010,  Pals and others 2011).
The US EPA regulates f ive haloacetic acids in drinking water, which are collectively
known as HAA5. Monochloro-, dichloro-, trichloro-, monobromo- and dibromoacetic
acids constitute the HAA5 and these have a total allowable limit of 60 ug L-1 in
drinking water (US EPA 2009).  The 2007 Philippine National Standards for Drinking
Water (PNSDW) drawn from the World Health Organization (WHO) register of
standard values for disinfection by-products include three haloacetic acids namely:
monochloroacetic acid at 0.02 mg L-1, dichloroacetic acid at 0.05 mg L-1, and
trichloroacetic acid at 0.2 mg L-1 (PNSDW 2007, WHO 2008). Of these compounds,
only dichloroacetic acid is categorized as Group B or possibly carcinogenic to humans
by the International Agency for Research on Cancer (WHO IARC 2004).  Nevertheless,
monochloroacetic acid and trichloroacetic acid have been reported to exhibit
cytotoxicity, genotoxicity, mutagenicity and teratogenicity in animal studies (Liang
and Singer 2003, Plewa and others 2010, Pals and others 2011).

Water is important not only for drinking but also for bathing and cleaning.  Likewise,
it is essential in recreational activities such as swimming, diving or water aerobics.
Swimming in pools, for example, provides exercise, relaxation, therapy and wellness
to man. For hygiene and health protection, swimming pool water is usually
disinfected. It has been shown that microorganisms can thrive in swimming pools
and cause outbreak of disease (Friedman and others 1999, Leoni and others 1999).
Chlorination is the disinfection method of choice for swimming pools because of
the residual effects of chlorine.  In some countries like Germany, it is recommended
to maintain chlorine levels of 0.3 to 0.6 mg L-1 or higher to safeguard the wellbeing



M.P.B. Espino and J.P. Mendoza

53

of the swimmers (Uhl and Hartmann 2005). Chlorinated swimming pool water has
more organic matter than chlorinated drinking water because of continuous inputs
from the swimmers. As a consequence, disinfection by-products including haloacetic
acids are formed in swimming pools. Likely, recirculation or reuse of this water
may result in disinfection by-products accumulation. Lee and others (2010)
demonstrated that haloacetic acids represent over 60% of the disinfection by-
products found in swimming pool waters in Korea which were treated with chlorine,
ozone-chlorine, or electrochemically-generated mixed oxidants.  In their chlorinated
water samples, haloacetic acids were measured at 14.1 to 636 ug L-1 concentrations.
Catto and others in 2012 reported haloacetic acids in water from two swimming
pools in Canada with concentrations of less than the limit of detection (<LOD) to
201.0 ug L-1.  In Swiss swimming pool waters, the haloacetic acids ranged from 0.9
to 240 ug L-1 where the concentrations of monochloroacetic acid alone were 11-
117 ug L-1 (Berg and others 2000). Haloacetic acids in water samples from swimming
pools in Portugal were detected in concentrations between 0.1 and 72.9 ug L-1 (Sa
and others 2000). The monochloroacetic acid in these samples ranged from 0.6 to
13.2 ug L-1.

Haloacetic acids in drinking water are commonly analyzed using US EPA Method
552.2. This method involves solvent extraction with methyl tert-butyl ether
(MTBE), methylation with 10% sulphuric acid in methanol, and determination by
gas chromatography-electron capture detection or GC-ECD.  Studies on the analysis
of haloacetic acids in swimming pool water are also carried out using US EPA
Method 552.2 (Lee and others 2010, Catto and others 2012). Berg and others
(2000) used diazomethane to derivatize the haloacetic acids before determination
by gas chromatography-mass spectrometry or GC-MS.  Sa and others (2012), on the
other hand, used dimethyl sulphate for derivatization and headspace solid phase
microextraction followed by GC-ECD.  Electrophoresis has also been demonstrated
to be an alternative method for haloacetic acids analysis particularly in drinking
water. Haloacetic acids may be extracted by solid-phase extraction (SPE) and
determined by capillary electrophoresis with diode array detection (Martinez and
others 1998), capillary electrophoresis with contactless conductivity detection
(Kuban and others 2012) or microchip capillary electrophoresis with capacitatively
coupled contactless conductivity detection (Ding and Rogers 2010). Capillary zone
electrophoresis with direct UV detection and contactless conductivity detection
w a s  u s ed  by Lo p ez- Av i l a  a n d  o t h e r s  ( 2 0 0 3 ) . Ca r r e r o  a n d  Ru s l i n g  ( 1 9 9 9 )
demonstrated the use of high pressure liquid chromatography and an electrochemical
detector coated with a f ilm of naf ion and dido-decyldimethylammonium bromide
in haloacetic acids determination. Ion chromatography or IC is another technique
for haloacetic acids analysis. Direct injection ion chromatography and mass



Determination of Monochloroacetic Acid in Swimming Pool Water

54

spectrometry (MS) were used to determine trace levels of haloacetic acids in drinking
water (Matthew and others 2009). Solid-phase extraction followed by ion-pair
liquid chromatography with electrospray ionization-mass spectrometry was also
used to study haloacetic acids in different water samples including tap, river and
swimming pool waters (Loos and Barcelo 2001, Prieto-Blanco and others 2012).
Sun and Gu (2007) used ion chromatography with suppressed conductivity to
determine haloacetic acids in chlorinated hospital effluents.

Monochloro-, monobromo- and bromochloroacetic acids were reported to be detected
in Metro Manila drinking water samples (Rodriguez and Espino 2010).  Only
monochloroacetic acid was quantif ied and it was found to be in 19-157 ug L-1

concentrations. The analytical method was a modif ied US EPA Method 552.2 in
which diethyl ether was used as extraction solvent instead of MTBE, resulting in
low recoveries. This preliminary study demonstrated that haloacetic acids may be
formed in the water supplies in Metro Manila. It was thus deemed that haloacetic
acids may also occur in recreational waters such as in swimming pools where
expectedly the water source would come from the main distribution lines of the
drinking water supply.

The aim of this present study was to develop and optimize an ion chromatographic-
conductivity detection method for monochloroacetic acid in swimming pool water.
If detected in the water samples, monochloroacetic acid may serve as a marker for
the occurrence of disinfection by-products including the other priority haloacetic
acids.

EXPERIMENTAL METHOD

Chemicals and Solvents

Chloride and bromide analytical standards, both labeled IC standard in 100 mL of
1 0 0 0  µ g  m L - 1 , w e r e  p u r c h a s e d  f r o m  F l u k a  ( B u c h s , S w i t z e r l a n d ) . T h e
monochloroacetic acid analytical standard (99.9% chloroacetic acid, 1000 mg/
ampule) was purchased from Sigma-Aldrich (St. Louis, MO, USA). The seven
calibration solutions of these standards were in the range of 0.05 to 1 mg L-1.  All
solutions were prepared in Absolute® distilled water (Asia Brewery Inc. , Philippines).

The mobile phase was a mixture consisting of 3.2 mM Na
2
CO

3
 and 1.0 mM NaHCO

3

prepared by dissolving appropriate amounts of NaHCO
3
 and Na

2
CO

3
 (J.T. Baker,

Philipsburg, NJ, USA) in distilled water. The 100 mM H
2
SO

4
 regenerant solution

used in the anion conductivity suppressor device was prepared from 18 M H
2
SO

4

solution (Labscan, Bangkok, Thailand).



M.P.B. Espino and J.P. Mendoza

55

Ordinary tap water, swimming pool water and bottled water (Summit® and Evian®

bottled drinking water purchased from a local supermarket) were used in spiking
and recovery experiments.

Sample Collection and Preparation

Surface water samples were taken from six Quezon City swimming pools in August
19-28, 2012.  These pools are rectangular in shape and small to medium in size,
typical of swimming pool facilities in Metro Manila. These were generally f illed
with chlorinated water from the tap. The water samples were collected in clean
500-mL PET bottled water containers; headspace was avoided during collection.
The containers were then sealed, covered on the outside with paper, and brought
immediately to the laboratory for analysis. The samples were f iltered through
125 mm Whatman Grade No. 40 f ilters (Whatman, NJ, USA). For chloride and bromide
determination, the samples were diluted 20 to 150 times with distilled water to
appropriate concentrations such that the analytes can be measured against the
calibration solutions. Before injection into the ion chromatograph, the samples
were f iltered using 0.45 um nylon syringe f ilters (Whatman, NJ, USA). For
monochloroacetic acid determination, undiluted swimming pool water samples were
passed through 2.5 cc Dionex II OnGuard Ag/H cartridges (Thermo Scientif ic,
Waltham, MA, USA).  Prior to use, the cartridges were conditioned with 15 mL
distilled water. Eight milliliters of the samples were passed through the cartridges.
The f irst 6 mL fractions were discarded, while the last 2 mL fractions were used for
monochloroacetic acid analysis.

The swimming pool water samples were also measured for pH using a Milwaukee
pH 600 pocket-sized pH meter (Milwaukee, NC, USA) as well as ultraviolet
absorbance at 254 nm using a UV mini 1240 UV-Vis spectrophotometer (Shimadzu,
Kyoto, Japan).

Instrumentation

A  M e t r o h m  8 8 1  C o m p a c t  I C  P r o  ( M e t r o h m  A G ,  H e r i s a u ,  S w i t z e r l a n d )  i o n
chromatographic system was used. The ion chromatograph was equipped with a
sample and eluent degasser, chemical suppressor device, high-pressure pump, six-
port injection valve, column heater, and conductivity detector. The ions were
separated on an anion column (Metrohm Metrosep A Supp 5-150) with dimensions
of 150 mm x 4.0 mm and a stationary phase material containing polyvinyl alcohol
plus quaternary ammonium groups. The guard column used was a Metrohm 5 mm x
4 mm Metrosep A Supp 4/5. Samples and standard solutions were introduced into
a f ixed 20-uL loop using a 10-mL syringe. The 3.2 mM Na

2
CO

3 
-1.0 mM NaHCO

3



Determination of Monochloroacetic Acid in Swimming Pool Water

56

mobile phase had a constant flow rate of 0.50 mL min-1 which resulted in a total
run time of 13 min. Monochloroacetic acid, chloride and bromide elute at 6.3, 7.1
and 10.5 min, respectively.  Data acquisition and processing were performed using
MagIC Net 2.2 chromatography software.

Analysis and Quantitation

Twenty microliters of the calibration solutions and water samples were injected
into the ion chromatograph. Blank solutions (distilled water) were injected at the
start of the analysis and after each injection of relatively high concentrations of the
analytes to flush the system as well as avoid baseline drift. No peaks were observed
at the retention times of the analytes in the blank solutions. The target analytes
were separated on the anion analytical column using a 3.2 mM Na

2
CO

3
-1.0 mM

NaHCO
3
 mobile phase at 25 oC. All measurements were done in three replicates.

More replicate measurements were done for validation, specif ically for recovery
and detection limit determinations.  Monochloroacetic acid, chloride and bromide in
the water samples were quantif ied by external calibration and linear regression
techniques. Data analyses including computations of detection limits, recoveries,
concentrations and standard deviations were performed using Excel Microsoft Office
2 0 0 7.

RESULTS AND DISCUSSION

Ion Chromatographic Determination of Monochloroacetic Acid,
Chloride and Bromide

The analytical determination of monochloroacetic acid in water was performed on
an anion column and initially using different mobile phases of various proportions
of Na

2
CO

3
 and NaHCO

3
.  At the f inal conditions of 3.2 mM Na

2
CO

3 
-1.0 mM NaHCO

3

mobile phase, 0.5 mL min-1 flow and 25oC, monochloroacetic acid eluted at 6.3
min. Monochloroacetic acid is detectable in water solutions containing low
concentrations of chloride and bromide. The simultaneous determination of the
three analytes is shown in Figure 1 where monochloroacetic acid, chloride and
bromide were separately eluted on the anion column at the optimum conditions.
The linear range for the determination of these analytes was from 0.05 to 1.0 mg
L-1 with correlation coeff icients, r2, of 0.9986-0.9993 (Figure 2).  The instrument
detection limits (IDL) were 0.01, 0.02 and 0.05 mg L-1 for chloride, monochloroactic
acid and bromide, respectively (Table 1).  The repeatability of the determination
method was good with percent RSD of 0.052-0.27% for these analytes.

The 0.02 mg L -1 detection limit for monochloroacetic acid using this ion
chromatographic method is comparable to that of the GC-ECD method developed



M.P.B. Espino and J.P. Mendoza

57

Figure 1. Ion chromatograms of 0.6 mg L-1  monochloroacetic acid (MCAA), chloride
and bromide spiked in [A] bottled water and [B] tap water. Conditions: 3.2 mM
Na

2
CO

3
/1.0 mM NaHCO

3
 mobile phase, 0.5 mL min-1 flow rate, 20 uL injection

volume.

 

y  = 0 .0 4 7 9 x  -  0 .0 0 1 4
R 2  =  0 . 9 9 9 2

y  =  0 .2 6 3 1 x  +  0 .0 0 0 5
R 2  =  0 . 9 9 8 6

y  =  0 .0 9 0 1 x  +  0 .0 0 7 3
R 2  =  0 . 9 9 9 3

0

0 .0 5

0 .1

0 .1 5

0 .2

0 .2 5

0 .3

0 0 . 2 0 .4 0 .6 0 .8 1 1 . 2

C o n ce n tr a ti o n ,  m g  L -1

A
re

a,
 (

µ
S

/c
m

)x
m

in

M CA A C hlo ride Bro m ide

Figure 2. Calibration plots of 0.05 to 1 mg L-1 monochloroacetic acid (MCAA),
chloride and bromide solutions (n=3 for each concentration).



Determination of Monochloroacetic Acid in Swimming Pool Water

58

and optimized by Rodriguez and Espino (2010). Using GC-ECD, monochloroacetic
acid that was derivatized with acidif ied methanol had a quantitation limit of 0.0169
mg L -1.  However, this method had low recoveries mainly due to the sample
preparation steps involved,  including microextraction, derivatization and
preconcentration. Table 2 summarizes the recoveries of monochloroacetic acid
spiked in two brands of commercial bottled water, tap water and swimming pool
water and analysed by ion chromatography-conductivity detection.  At spike levels
of 0.1 to 0.6 mg L-1, the recoveries were between 43 and 122%.  In the GC-ECD
method, the recovery of monochloroacetic acid spiked in ultrapure water was only
16.4%.

The detection limit for monochloroacetic acid in this present study is also
comparable to the detection limits of other methods reported in literature.  Sun
a n d  G u  ( 2 0 0 7 )  s t u d i e d  h a l o a c e t i c  a c i d s  i n  h o s p i t a l  e f f l u e n t s  u s i n g  i o n
chromatography and reported a monochloroacetic acid detection limit of 0.01235
mg L-1.  HPLC with electrochemical detection was also used for monochloroacetic
acid determination with a relatively high detection limit of 10 mg L-1 (Carrero and
Rusling 1999). Various electrophoresis methods were also reported in which the
detection limits were 2.1-2.7 mg L-1 (Ding and Rogers 2010), 0.044 mg L-1 (Kuban
and others 2012), and 0.005 mg L-1 (Martinez and Calull 1998).   Matthew and others
(2009) studied haloacetic acids in drinking water using ion chromatography-mass
s p e c t r o m e t r y w i t h  a  s u p e r i o r  d e t e c t i o n  l i m i t  o f  2 . 1 5 8 x 1 0 - 5 m g  L - 1  f o r
monochloroacetic acid. It should be noted that the recoveries of these methods
varied widely as the sample preparation involved different extraction and pre-
treatment techniques using a variety of sorbent materials.

Monochloroacetic acid 6.3 0.05-1.0 0.9992 0.052 0.02
 (0.03) (15)

Chloride 7.1 0.05-1.0 0.9986 0.27 0.01
 (0.05) (8)

Bromide 10.5 0.05-1.0 0.9993 0.11 0.05
 (0.1) (8)

Analyte

Retention
time, min
(SD), n=3

Linear
range,
mg L-1

Correlation
coeff icient,
       R2

Repeatabilitya

of peak area,
(µS/cm) x min

(% RSD)
n=10

IDLb

mg L-1

a Interday analyses of a 1 mg L-1 standard solution for 6 days
b Measured using a 0.05 mg L-1 standard solution; IDL= SD x 3.143 (n=7; student’s t-value
at 99% confidence level)

Table 1. Analytical performance of the optimized ion chromatographic method



M.P.B. Espino and J.P. Mendoza

59

For chloride and bromide determination in this study, the detection limits were a
little higher than those of the sequential chemical and CO

2
-suppressed ion

chromatographic method reported by De Vera and Espino in 2011.  With chemical
and CO

2
 suppression, the background conductivity was reduced, which resulted in

lower detection limits for chloride and bromide at 0.001 and 0.007 mg L -1,
respectively.  This tandem suppression technique was used solely for the analysis
of inorganic anions namely fluoride, chloride, bromide, nitrate, phosphate and
sulphate.  The recoveries of these anions in ultrapure water ranged from 94 to
154%. In this present study wherein the ion chromatographic method involved
only chemical suppression for detection, the recoveries of chloride and bromide in
bottled, tap and swimming pool waters ranged between 28 and 121%. This wider
range of recoveries may be attributed to the different water matrices that were
used.

Overall, the optimized ion chromatography with conductivity detection method
developed in this study has low detection limits, relatively low linear concentration
range for trace analysis, good reproducibility, and acceptable recoveries.

Bottled water:
A

low (0.1 mg L-1) 100 (17)   73(  4) 43 (10)
high (0.4 mg L-1) 117 (15)   82(  4) 67 (  7)

B
low (0.2 mg L-1)   70 (17)   71 (  2) 51 (10)
high (0.4 mg L-1)   65 (16)   90 (  8) 72 (14)

Tap water
low (0.2 mg L-1)   82 (14) 121 (14 ) 72 (  6)
high (0.6 mg L-1)   76 (  2)   79 (  1) 86 (  2)

Swimming pool water*
low (0.2 mg L-1) 122 (36) 102 (15) 28 (  4)
high (0.6 mg L-1)   43 (  0)   95 (  1) 65 (  2)

A= Summit®; B= Evian®; *Swimming pool water sample that does not
contain monochloroacetic acid was used

Spiked Water

% Recoveries (SD), n=3

Monochloroacetic
acid

Chloride Bromide

Table 2 Percent recoveries in d ifferent water matrices



Determination of Monochloroacetic Acid in Swimming Pool Water

60

Analysis of Monochloroacetic Acid in Swimming Pool Water

The applicability of the ion chromatography-conductivity detection method was
tested in the analysis of monochloroacetic acid in swimming pool water samples.
I n  w a t e r  c o n t a i n i n g  h i g h  c o n c e n t r a t i o n s  o f  c h l o r i d e ,  t h e  d e t e c t i o n  o f
monochloroacetic acid was found to be affected by the large chloride ion signal.
Thus, the analysis of monochloroacetic acid and chloride in highly chlorinated water
samples requires special sample preparation. Dilution was necessary particularly
for chloride determination because the concentration was anticipated to be above
the highest concentration in the established linear range of the optimized method.
Monochloroacetic acid was separately analysed after chloride was removed from
the sample or after its concentration was minimized.

An Ag/H cartridge was used for the sample preparation in the analysis of
monochloroacetic acid in chlorinated swimming pool water.  This cartridge consists
of layers of Ag and H resins that retain chloride, bromide, iodide and carbonate ions.
Figure 3 compares the ion chromatograms of a swimming pool water sample that
was not passed through an Ag/H cartridge and the same water sample that was
passed though an Ag/H cartridge. The use of an Ag/H cartridge minimized the signal
due to chloride allowing the detection and quantitation of monochloroacetic acid.

Figure 3. Ion chromatograms of [A] a swimming pool water sample and [B] the
same swimming pool water sample after passing through an OnGuard Ag/H cartridge.
Conditions: 3.2 mM Na

2
CO

3
/1.0 mM NaHCO

3
 mobile phase, 0.5 mL min-1 flow rate,

20 uL injection volume.



M.P.B. Espino and J.P. Mendoza

61

In a spiking experiment of 0.6 mg L-1 monochloroacetic acid and chloride in distilled
water using Ag/H cartridges, the retention time of monochloroacetic acid on the
anion column was invariable at 6.3 min and the recovery was good at 122% (n=6,
SD 13).

Monochloroacetic acid, chloride and bromide concentrations in six swimming pool
water samples were determined using the optimized ion chromatography-
conductivity detection method.  Because the Ag/H cartridge removes the inorganic
anions, chloride and bromide were determined separately without pre-treatment
using Ag/H cartridges.  Monochloroacetic acid was detected in the swimming pool
water samples with an average pH of 7.1 and high chloride concentrations.
Monochloroacetic acid was found in three of the six samples with concentrations
r a n g i n g  f r o m  0 . 0 2 0  to  0 . 0 9 3  m g  L -1 ( Ta b l e  3 ) . T h e  c h l o r i d e  a n d  b r o m i d e
concentrations in all samples were 24-104 mg L-1 and 0.16-7.52 mg L-1, respectively.
These water samples registered UV absorbances at 254 nm ranging from 0.002 to
0.060 a.u. , suggesting the presence of dissolved organic compounds which may
serve as precursors of monochloroacetic acid.  Bromide found in the water samples
also indicate the possible occurrence of brominated haloacetic acids such as
monobromo- and dibromoacetic acids belonging to the f ive regulated haloacetic
acids.  And because monochloroacetic acid was detected in the swimming pool

Table 3. Concentrations of monochloroacetic acid, chloride
and bromide in swimming pool water samples

a n=3
b Measured using water samples diluted 20, 50, 80, 100 or 150x depending on the response
which should be within the range of the calibration solutions

A 8/19/12 6.8 0.002 0.020 104 5.98
 (0) (0) (0)

B 8/22/12 6.9 0.010 not detected   66 2.04
(0.69) (0.97)

C 8/22/12 6.5 0.002 not detected   24 1.86
(0.34) (0.58)

D 8/22/12 7.1 0.012 0.083(0)   67 7.52
(0.96) (1.89)

E 8/28/12 7.8 0.014 0.093(0)   53 0.80
(0.50) (0.47)

F 8/28/12 7.6 0.060 not detected   24 0.16
(0.13) (0)

Water
Sample

Code

Sampl ing
Date

pH Absorbance
at 254 nm

Mean Concentration in mg L-1 (%RSD)a

Monochloroacetic
Acid

Chlorideb Bromideb



Determination of Monochloroacetic Acid in Swimming Pool Water

62

water samples, it could be expected that other disinfection by-products may also
be present.  The concentrations of monochloroacetic acid found in these swimming
pool samples are within the 0.011-0.117 mg L-1 range of monochloroacetic acid
concentrations in Swiss swimming pools reported by Berg and others (2000).
However, the concentrations are relatively high compared to the 0.0006-0.0132
mg L-1 monocloroacetic acid concentrations in swimming pools in Portugal (Sa and
others 2012).  To the best of our knowledge, this is the f irst study on the occurrence
of the disinfection by-product monochloroacetic acid in the swimming pools in the
Philippines. Although disinfection by-products such as trihalomethanes and
haloacetic acids have been studied in the local drinking water supplies (Rodriguez
and others 2006, Rodriguez and others 2010), these compounds have not been
studied yet in the local swimming pool waters.

Ion chromatography- Ag/H cartridge 0.02 mg L-1 0.05-1.0 122   This study
conductivity mg L-1 (0.2 mg L-1

detection spike level in
swimming

pool water and
0.6 mg L-1 in

distilled
water)

GC-MS MTBE extraction; 2 ng L-1 0-0.005 96 Berg and
diazomethane mg L-1 (100-430 others
derivatization ng L-1 spike 2000

level in
nanopure

water)
GC-ECD MTBE extraction; n o t n o t n o t Lee and

10% sulfuric acid reported reported reported others
in methanol 2010
derivatization

GC-ECD MTBE extraction; 0.1-1.6 n o t n o t Catto and
10% sulfuric acid  µg L-1 reported reported others
in methanol 2012
derivatization

GC-ECD MTBE extraction; 1.3 µg L-1 n o t n o t Simard
10% sulfuric acid reported reported and others
in methanol 2013
derivatization

Ultraperformance Membrane-protected 0.07 µg L-1 1-150 91.6-95.1 Nsubuga
liquid chromatography- micro-solid phase µg L-1 (10 µg L-1 and
diode array detection extraction spike level in Basheer

swimming 2013
pool water)

Table 4.  Comparison of analytical methods
for monochloroacetic acid in swimming pool water

Method performance

Analytical
technique

Sample
preparation LOD Linearity

%
Recoveries

Reference



M.P.B. Espino and J.P. Mendoza

63

Table 4 lists analytical methods used in the determination of monochloroacetic
acid in swimming pool water. The main advantage of the ion chromatographic method
used in this present study is that it eliminates the use of harmful derivatization
reagents such as diazomethane and extraction solvents such as MTBE. Solvent
extraction and GC-ECD or MS are the common techniques in monochloroacetic acid
analysis and when combined with sample preconcentration steps, very low detection
limits can be achieved such as those reported by Catto and others (2012), and Berg
and others (2000).  Although the detection limit of monochloroacetic acid using the
ion chromatographic method is relatively high, this method is less costly and easier
to use than the GC-based methods.

The results of this initial study prompt the need to examine further the occurrence
of disinfection by-products in swimming pool waters in order to protect the public
from exposure to these compounds. Extensive data are required as basis for setting
up measures in minimizing the levels of disinfection by-products in public
swimming pools.

The analytical method involving ion chromatography with conductivity detection
developed in this study provides a simple method for use in determining
monochloroacetic acid in swimming pool water.  In addition, this method has potential
application in the determination of monochloroacetic acid in chlorinated drinking
water.  The method may be used by laboratories of water providers and regulatory
agencies in the Philippines. If used in drinking water analysis, a pre-concentration
step may be necessary because drinking water contains less organic matter than
swimming pool water; thus, the monochloroacetic acid concentration may be lower.
The 2007 Philippine National Standards for Drinking Water stipulates that mono-
chloroacetic acid in our drinking water should not exceed 0.02 mg L-1. The ion
chromatographic method presented in this study has a detection limit of 0.02 mg L-1.
This is thus an available method for detecting monochloroacetic acid in
concentrations above the guideline value for drinking water.  This method can still
be modif ied and improved if used in the determination of very low concentrations
of monochloroacetic acid (<0.02 mg L-1) especially in relatively clean water such
as drinking water. The detection limit can be lowered with the use of SPE and
preconcentration steps and more sensitive detection techniques such as mass
spectrometry in ion chromatography. Nonetheless, this method in its present form
can still be used in compliance monitoring of monochloroacetic acid in the local
water supplies.



Determination of Monochloroacetic Acid in Swimming Pool Water

64

CONCLUSIONS

Ion chromatography with conductivity detection is applicable for the determination
of monochloroacetic acid in swimming pool water.  This method has low detection
limit at 0.02 mg L-1.  It is reproducible and does not require harmful reagents such
as diazomethane and MTBE extraction solvent. Low concentration chloride and
bromide may be analyzed together with monochloroacetic acid in water using the
optimized ion chromatographic method. In high chloride content water samples
like swimming pool water, an Ag/H car tridge is necessary for monochloroacetic
acid determination. The detection of monochloroacetic acid in the water of some
swimming pools studied suggest the need to further investigate the occurrence of
monochloroacetic acid as well as the other disinfection by-products in swimming
pools in order to protect public health.

ACKNOWLEDGMENTS

M.P.B. Espino thanks the UP Diliman Natural Science Research Institute for the
research grant through Project No. CHE-12-2-07.  Dr. Nathaniel Diola and Engineer
Mabel Globio are gratefully acknowledged for allowing us to use their ion
chromatograph at their Construction Materials and Structures Laboratory, UP Diliman
College of Engineering. We also thank the people who provided the water samples
used in this study and the reviewers for their suggestions to improve the manuscript.

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_______________

Maria Pythias B. Espino, PhD <mbespino@upd.edu.ph> is an Associate Professor
at the Institute of Chemistry, University of the Philippines Diliman.

Jamie P. Mendoza was a University Research Associate at the Natural Science
Research Institute and is currently a graduate student at the College of Science,
University of the Philippines Diliman.