Perchlorate occurrence in foodstuffs and water: Analytical methods and techniques for removal from water - A review

Perchlorate (ClO₄^-), a type of contaminant with high diffusivity and durability, has been widely detected in water and foodstuffs, arousing a global concern. It can interfere with normal function of the human thyroid gland, affecting human health. Therefore, determination of perchlorate in water and foodstuffs, and removal from water are important. This review focuses on the occurrence of perchlorate, mainly in water and foodstuffs, and provides an overview of analytical methods for determination of perchlorate over the last two decades. In addition, merits and drawbacks of the various methods have been considered. This review also highlights the most commonly used approaches for removal of perchlorate from water. Finally, current trends and future perspectives in determination of perchlorate and removal from water are proposed. This review provided a comprehensive understanding of perchlorate occurrence and its removal from water, and had practical significance in reducing the harm of perchlorate to human.

Rapid determination of polar pesticides and plant growth regulators in fruits and vegetables by liquid chromatography/tandem mass spectrometry

A simple high-throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) multiresidue analysis method was developed for the simultaneous determination of polar pesticides, plant growth regulators and other polar compounds. These included amitrole, chlormequat, mepiquat, cyromazine, ETU, PTU, perchlorate, and daminozide using a mixed-mode column. A 10 g test portion was shaken with acidified methanol for 10 min. After centrifugation, the sample extract was injected and analyzed within 11 min by LC-MS-MS. This column eliminated the need for derivatization or the use of ion paring reagent. Two MS-MS transitions were monitored in the method for each target compound to achieve true positive identification. Eight isotopically-labeled internal standards corresponding to each analyte were used to correct for matrix suppression effect and/or instrument signal drift. The average recovery for all analytes at 20, 40, and 250 ng/g (n = 6) ranged from 73-136%, with a relative standard deviation of ≤ 20%.

Perchlorate contamination of groundwater from fireworks manufacturing area in South India

Perchlorate contamination was investigated in groundwater and surface water from Sivakasi and Madurai in the Tamil Nadu State of South India. Sensitive determination of perchlorate (LOQ = 0.005 μg/L) was achieved by large-volume (500 μL) injection ion chromatography coupled with tandem mass spectrometry. Concentrations of perchlorate were <0.005-7,690 μg/L in groundwater (n = 60), <0.005-30.2 μg/L in surface water (n = 11), and 0.063-0.393 μg/L in tap water (n = 3). Levels in groundwater were significantly higher in the fireworks factory area than in the other locations, indicating that the fireworks and safety match industries are principal sources of perchlorate pollution. This is the first study that reports the contamination status of perchlorate in this area and reveals firework manufacture to be the pollution source. Since perchlorate levels in 17 out of 57 groundwater samples from Sivakasi, and none from Madurai, exceeded the drinking water guideline level proposed by USEPA (15 μg/L), further investigation on human health is warranted.

Analysis of perchlorate in milk powder and milk by hydrophilic interaction chromatography combined with tandem mass spectrometry

A simple, selective, and sensitive method using hydrophilic interaction chromatography combined with tandem mass spectrometry (HILIC-MS/MS) for quantifying perchlorate in milk powder and milk was developed. The analysis was conducted on an Inertsil HILIC column (150 mm x 3.0 mm, 3.5 mum) using a mobile phase consisting of methanol and 0.1% formic acid (60:40, v/v). The detection was performed by MS/MS via electrospray ionization. Linear calibration curves were obtained in the concentration range of 2.00 x 10(-2) to 8.00 microg/g and 4.00 x 10(-1) to 20.0 microg/L for perchlorate in milk powder and milk, respectively. The method detection limit was 4.00 x 10(-3) microg/g for milk powder and 8.00 x 10(-2) microg/L for milk. The recoveries of perchlorate in milk powder and milk were all >90%. This method was successfully applied to the quantitative determination of perchlorate in milk powder and milk.