Determination of chlorate, perchlorate and bromate anions in water samples by microbore reversed-phase liquid chromatography coupled to sonic-spray ionization mass spectrometry

Engineering of a Bacterial Biosensor for the Detection of Chlorate in Food

Chlorate can contaminate food due to the use of chlorinated water for processing or equipment disinfection. Chronic exposure to chlorate in food and drinking water is a potential health concern. The current methods for detecting chlorate in liquids and foods are expensive and not easily accessible to all laboratories, highlighting an urgent need for a simple and cost-effective method. The discovery of the adaptation mechanism of Escherichia coli to chlorate stress, which involves the production of the periplasmic Methionine Sulfoxide Reductase (MsrP), prompted us to use an E. coli strain with an msrP-lacZ fusion as a biosensor for detecting chlorate. Our study aimed to optimize the bacterial biosensor's sensitivity and efficiency to detect chlorate in various food samples using synthetic biology and adapted growth conditions. Our results demonstrate successful biosensor enhancement and provide proof of concept for detecting chlorate in food samples.

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.

Determination of Trace Bromate in Drinking Water with High Chloride Matrix by Cyclic Ion Chromatography

An ion chromatography (IC) system with switching recycling column was developed for the determination of bromate in drinking water with high chloride content. The system included a pump, two switching valves, guard column and analytical column, suppressor and a conductivity detector. In this method, the single eluent was used for both online collection and matrix elimination, and bromate was eluted from the concentrator column to the analytical column circularly. Under the optimized separation conditions, the method showed good linearity (r = 0.9995) in the range of 1-100 μg/L and repeatability (RSD ≤ 4.80%, n = 6). The limit of detection was 0.2 μg/L (S/N = 3) with 1000 μL sample volume injections. The method was applied to analysis of drinking and tap waters, and satisfactory recoveries of spiked samples between 96.8% and 108.7% were obtained. The result showed that the recycling column-switching system can be useful for the determination of traces of bromate in high-chloride samples, which is required in production of the drinking water and quality control of the final product.

LC-ESI-MS/MS determination of oxyhalides (chlorate, perchlorate and bromate) in food and water samples, and chlorate on household water treatment devices along with perchlorate in plants

The results of the validation study of the LC-ESI-MS/MS method for the determination of chlorate (ClO₃^-), perchlorate (ClO₄^-) and bromate (BrO₃^-) in water and food samples are summarized. Towards this, 284 samples of drinking water were analysed, out of which the 69% contained chlorate above the limit of quantitation (LOQ) of 0.01 mg/L, with maximum amount of 1.1 mg/L. Only 6 samples were found to be positive with perchlorate at levels <0.01 mg/L. Bromate was detected in 5 drinking water samples at levels above the LOQ, at concentrations up to 0.026 mg/L. For the validation of the method in food, 108 blank samples were spiked with chlorate and perchlorate for the LC-MS/MS analysis at two levels. In total 247 food samples from the market of 19 different commodities including fruits, vegetables, cereals and wine, were analysed. The maximum concentration of chlorate was found at 0.83 mg/kg in a sample of cultivated mushrooms. The number of samples contaminated with perchlorate was also small, with all the determined concentrations below the LOQ of 0.05 mg/kg. Experiments for the chlorate reduction in drinking water, showed that reverse osmosis treatment is effective in particular with newly installed cartridges. Finally, according to the results of the pilot study when chlorinated water is used for the plant irrigation, accumulation of chlorate is observed, especially in the green parts of the plant. Perchlorate was also detected in leafy samples, although it was not present in the irrigation water.