Determination of Trace Perchlorate in Drinking Water by

Developing Ion Chromatography Coupled with Mass

Spectrometry (IC-MS)

Y M Xu

, H J Guo

, H Y Ning

, H W Yuan

, X Hu

, J He

1,2

, P C Pan

1,2

and H

Chen

2,*

Sichuan West Analytical Testing Co., Ltd., Chengdu, 610101, China

Sichuan Institute of Atomic Energy, Chengdu, 610101, China

Corresponding author and e-mail: H Chen, haochen@siae.cn

Abstract. Perchlorate (ClO

) in drinking water poses healthy risk for human beings. The

routine method of IonPac AS16 polarizable anion analytical column to analyze ClO

drinking water failed due to the false positive behavior of perchloric acid. Therefore, an ion

chromatography coupled with mass spectrometry (IC-MS) method was developed to

determine the content of ClO

in drinking water based onIonPac AS20 column, 45 mM KOH

eluent and negative ion mode of mass spectrometry. The results show that the ClO

concentration displayed an excellent linear performance in the range of 1-20μg/L using the

newly developed method, its method detection limit (MDL) was determined to be 0.47μg/L,

and the recoveries of the spiked samples ranged from 92.0% to 101.5%, meeting the relevant

requirements of GB/T 6379.6-2009.

1. Introduction

Perchlorate (ClO

) has been widely used in many fields, such as rocket propellants, fireworks

manufacturing, arms industry, car airbag, highway safety flash board, etc[1]. Perchlorate is

chemical stable and highly soluble in water, so with entering into environment during industrial

production and discharge, it goes easily into the underground water, causing water pollution. These

contaminated water often harms human health through the food chain or drinking water[2,3].

Recently, overdose of perchlorate has been detected in the Chinese tea exported to Europe. So

European Union (EU) is preparing to set more strict standards to limit the importation of high

perchlorate-containing Chinese tea, which is causing more concern. In the late 2015, EU required the

maximum content of 0.75 mg/kg for the perchlorate in tea in the proposal of Circular on the Standard

for Perchlorate and Anthraquinone Content in Tea in the EU. It has been reported[4-6] that the ionic

radius of ClO

is very close to that of iodide (I) ions, so it tends to diffuse into the thyroid competed

with I ions, hinders the absorption of I ions in thyroid, decreasing the synthesis of thyroid hormone,

and resulting in metabolism of human body in disorder. The higher ClO

content even leads to

thyroid cancer. Especially, it is more harmful for the growth and development of fetal and infant

central nervous system.

266

Xu, Y., Guo, H., Ning, H., Yuan, H., Hu, X., He, J., Pan, P. and Chen, H.

Determination of Trace Perchlorate in Drinking Water by Developing Ion Chromatography Coupled with Mass Spectrometry (IC-MS).

In Proceedings of the International Workshop on Environmental Management, Science and Engineering (IWEMSE 2018), pages 266-271

ISBN: 978-989-758-344-5

Based on the above issues, American Environmental Protection Organization (EPA) has enacted

the Safe Drinking Water Act in which perchlorate is listed as one of the environmental pollutants, and

established a national standard for drinking water[7-8] that the reference dose of perchlorate for

human health is 0.7 μg/kg per day, that is, the concentration of perchlorate in drinking water is less

than 24.5 μg/L. Wu et al. [9] conducted a preliminary investigation on the perchlorate content of 300

water samples from 15 sites in 13 provinces in China and found that 86% of the water samples

contained perchlorate at a concentration ranging from 0.02 μg/L to 54.4 μg/L. Perchlorate pollution

was found in Liuyang City[10], China's largest fireworks production base. In addition, the

perchlorate concentration in the dust of northern China was in the range of 0.132-5300 mg/kg[11].

While in southern India, the perchlorate concentration in groundwater ranged from 0.005 to 7690

μg/L[12]. Apparently, perchlorate pollution of drinking water has become more and more global,

widespread and serious.

Over the years, the rapid development of ion chromatography and high sensitive techniques made

the analysis of trace perchlorate more accurate.

EPA has developed ion chromatography as the standard method 314.0[13]. However, with the

technological development of analyzing perchlorate[14], it was found that during analyzing some

drinking water samples using IonPac AS16 column, the qualitative determination of perchloric acid

appeared false positive behavior with the issue of eluting both 4-chlorobenzenesulfonic acid and

perchlorate. For this problem, IonPac AS20 column has been improved by modifying the filler

structure with a high-capacity, anion-exchange column of hydroxide system. This structure could

greatly reduce the adsorption of perchlorate by the stationary phase of 4-chlorobenzenesulfonic acid

and eliminate the interference of 4-chlorobenzenesulfonic acid to determining perchlorate content. In

the present study, we select IonPac AS20 as the pretreatment separation column to determine trace

perchlorate.

2. Experimental

2.1. Instruments and reagents

Thermo Scientific Dionex ICS-5000

Ion Chromatography with EGC Eluent Auto-Generator,

Conductivity Detector and ChromeLeon 7 Chromatography workstation;

Thermo Scientific MSQ plus with Electrospray Ion (ESI) source;

Dionex AS20 chromatography column, 250 × 2 mm;

Dionex AERS500 anion suppressor, 2 mm;

Dionex EGC500 KOH eluent;

Millipore Direct Q-8 Ultrapure water purification system;

Ultrapure water, 18.2 MΩ·cm;

Sodium perchlorate standard, 1 mg/L.

2.2. Chromatographic conditions

Eluent: 45 mM KOH, at the same concentration, automatically generated online by the EGC Eluent

Auto-Generator;

Flow rate: 0.3 mL/min;

Injection volume: 150 μL;

Response signal: 70 mA.

2.3. MS conditions

Spray source temp.: 390 ℃;

Polarity: negative ion mode;

Spray pressure: 20 psi;

Determination of Trace Perchlorate in Drinking Water by Developing Ion Chromatography Coupled with Mass Spectrometry (IC-MS)

267

Probe voltage: -3 kV;

Declustering voltage: -40 V;

Probe temp.: 450

○

Selected Ion Monitoring (SIM) channel: 99, 101, and 107 mass/charge ratio (m/z);

Dwell time: 1 s;

Sampling time: 200 ms;

Run time: 18 min.

3. Results and discussion

3.1. Linear range, precision and detection limit

Configure a series of perchlorate standard solutions of 1, 2, 5, 10 and 20 μg/L respectively, inject 150

μL into mass spectrometry and record the peak area of perchlorate. The chromatogram and

calibration curve of perchlorate standard solutions are shown in Figure 1. The results show that the

method displays a good linearity in the range of 1~20 μg/L of perchlorate solutions, the linear

correlation coefficient r = 0.999. Table 1 shows the results from 7 replicate injections of 10 μg/L

perchlorate solution, and the values were calculated from an external standard calibration curve. The

method detection limit (MDL) is determined as 0.47 μg/L and the precision (relative standard

deviation, RSD) is 1.48%.

Figure 1. Chromatogram and calibration curve of perchlorate.

IWEMSE 2018 - International Workshop on Environmental Management, Science and Engineering

268

Table 1. MDL calculation using 10 μg/L perchlorate.

Replicate

Amount

(μg/L)

Average

(μg/L)

Standard deviation

(s.d., μg/L)

RSD

(%)

MDL

(3.14 × s.d., μg/L)

1 9.91

10.03 0.15 1.48 0.47

2 9.86

3 10.24

4 10.08

5 10.15

6 9.95

7 10.03

3.2. Sample analysis and spiked sample experiments

Taking tap water and bottled drinking water as samples, the samples were directly filtered through

0.22 μm aqueous membrane filter, and samples were spiked and analyzed respectively, the results are

shown in Figure 2 and Table 2. It can be seen that the recoveries of spiked samples are all in the

range of 92.0% ~ 101.5%, indicating that the method is accurate, stable and reliable.

Figure 2. Chromatogram of sample and spiked sample (bottled drinking water).

Determination of Trace Perchlorate in Drinking Water by Developing Ion Chromatography Coupled with Mass Spectrometry (IC-MS)

269

Table 2. Results of samples and spiked samples.

Samples

Amount

(samples,

μg/L)

Spiked

Amount

(μg/L)

Amount

(spiked samples,

μg/L)

Recoveries

(%)

tap wate

N.D. 2.0 1.84 92.0

bottled drinking

wate

N.D. 2.0 2.03 101.5

tap wate

N.D. 20.0 18.63 93.1

bottled drinking

wate

N.D. 20.0 19.54 97.7

tap wate

N.D. 50.0 47.27 94.5

bottled drinking

wate

N.D. 50.0 50.12 100.2

N.D.: Not be detected

4. Conclusions

In this paper, IC-MS method was developed to detect the trace perchlorate in drinking water, and

demonstrated low MDL, excellent precision and high accuracy which meet the relevant requirements

of GB/T 6379.6-2009 “Accuracy (trueness and precision) of measurement methods and results─Part

6: Use in practice of accuracy values”.

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