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

Presence of Chlorate and Perchlorate Residues in Raw Bovine Milk from Italian Farms

Chlorates and perchlorates are endocrine disruptors and emerging environmental contaminants found in various types of foods, including milk and dairy products. The presence of chlorate has been associated with the use of chlorine-based sanitizers to disinfect equipment and water used in food processing. Perchlorate, on the other hand, occurs naturally in the environment but is also released from anthropogenic sources. To protect consumers, the EU set an MRL for chlorate in milk but not for perchlorate. Considering that data on chlorates and perchlorates in this field are limited, the objective of this study was to assess the presence of these two anions in 148 samples of raw bovine milk collected from different farms of Lombardy and grouped in three different geographical zones. Chlorate was detected in 73% of the samples analyzed, at concentrations ranging from <LOQ to 18.70 μg kg−1 with an average value of 7.10 ± 5.88 μg kg−1 below the MRL; perchlorate with a frequency of 99%, in the range from <LOQ to 6.95 μg kg−1 and an average value of 4.06 ± 1.58 μg kg−1. No significant differences were detected among the three geographical zones. An evaluation of the estimated daily intake of perchlorate through milk confirmed the absence of risk for Italian consumers.

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.

Accurate, sensitive and rapid determination of perchlorate in tea by hydrophilic interaction chromatography-tandem mass spectrometry

Perchlorate is an environmental contaminant interrupting thyroid hormone production, and perchlorate in tea has raised wide concern recently. In this study, an accurate method was developed for the determination of perchlorate in tea using hydrophilic interaction chromatography-tandem mass spectrometry and a simplified QuEChERS procedure. The method utilized a zwitterion HILIC column for separation, and the optimal gradient eluents consisted of acetonitrile and aqueous solution with 0.1% formic acid and 20 mmol L^-1 ammonium formate. Calibration curves were fitted by the quadratic model with 1/x weight instead of the linear model. As perchlorate was only partially extractable when using acetonitrile or methanol as the extraction solvent, acetonitrile/water (1 : 1, v/v) was chosen to extract perchlorate from tea samples. Graphitized carbon black was used as the dispersive solid phase extraction sorbent to clean up tea extracts. The method exhibited satisfactory accuracy with recoveries of 81.4-100.9% and relative standard deviations of 1.3-14.5% for green and black teas. The limit of quantitation was 0.005 mg kg^-1, while the limits of detection were 0.0011 mg kg^-1 for green tea and 0.0013 mg kg^-1 for black tea, indicating an excellent sensitivity of this method. A 100% positive rate of perchlorate was found in 100 real tea samples, and the concentrations ranged from 0.0030 mg kg^-1 to 0.78 mg kg^-1. This accurate, sensitive and rapid method would be suitable for monitoring, risk assessment and source identification of perchlorate in tea.

One-step sample processing method for the determination of perchlorate in human urine, whole blood and breast milk using liquid chromatography tandem mass spectrometry

A one-step sample processing was developed to determine the levels of perchlorate in human urine, whole blood and breast milk by using liquid chromatography tandem mass spectrometry (LC-MS/MS). Athena C18-WP column was used to separate and analyze perchlorate. Perchlorate and isotope-labeled perchlorate (Cl¹⁸O₄^-) internal standards were spiked in the sample matrix through vortex mixing, centrifugation, and filtration. The filtrate was collected and subjected to LC analysis. The developed method was validated for its reproducibility, linearity, trueness, and recovery. Satisfactory recovery of perchlorate ranged from 81% to 117% with intraday relative standard deviations (RSDs) (n = 3) and inter-day RSDs (n = 9) of 5-18% and of 5-16%, respectively. Good linearity (R² ≥ 0.99) was observed. Limits of detection and quantification for perchlorate ranged from 0.06 µg/L to 0.3 µg/L and from 0.2 µg/L to 1 µg/L, respectively. Perchlorate concentrations were found in human urine (n = 38) and whole blood (n = 8) samples with the range of 6.5-288.6 µg/L and 0.3-2.8 µg/L, respectively. These results indicate the applicability of our developed method in determining perchlorate level in real samples. Moreover, this method is also highly reliable, sensitive and selective in detecting perchlorate in human urine, whole blood and breast milk samples and may be applicable to other matrixes i.e. saliva, serum, plasma, milk powder and dairy milk.

An Improved, Rapid, and Sensitive Ultra-High-Performance Liquid Chromatography-High-Resolution Orbitrap Mass Spectrometry Analysis for the Determination of Highly Polar Pesticides and Contaminants in Processed Fruits and Vegetables

A rapid, specific, and sensitive method based on quick polar pesticide extraction and ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry with an Orbitrap analyzer was evaluated. Usually, pesticides were analyzed individually using derivatization or ion-pairing techniques and detection by ion chromatography. We identified and simultaneously quantified 6 highly polar compounds (glyphosate, aminomethyl phosphonic acid (AMPA), phosphonic acid, fosetyl-Al, chlorate, and perchlorate) in 83 processed fruits and vegetables as well as 15 infant foods. Isotopically labeled internal standards ¹⁸O₄-perchlorate, ¹⁸O₃-chlorate, and ¹³C₂¹⁵N-glyphosate were applied to quantify five polar compounds and to compensate for any factor affecting the recovery rates. Only AMPA was quantified using a standard addition approach to compensate for matrix effects. This analytical methodology is fast and reliable, and it is also able to satisfy the strict requirements of infant food analysis.

Development and Validation of Ion Chromatography-Tandem Mass Spectrometry-Based Method for the Multiresidue Determination of Polar Ionic Pesticides in Food

An extraction method using acidified methanol based on the quick polar pesticide (QuPPe) method using suppressed ion chromatography coupled to mass spectrometry was developed and validated for the direct analysis of polar pesticides, without the need for derivatization or ion pairing, in cereals and grapes. The method was robust, and results for glyphosate, aminomethyl phosphonic acid (AMPA), N-acetyl-AMPA, glufosinate, 3-methylphosphinicopropionic acid (3-MPPA), N-acetyl glufosinate, ethephon, chlorate, perchlorate, fosetyl aluminum, and phosphonic acid at three concentration levels (typically 0.01, 0.05, and 0.1 mg/kg) were compliant with SANTE/11945/2015 guideline method performance criteria. Cereal-based infant food proved to be a more challenging matrix and validated only for glyphosate, chlorate, and perchlorate at 0.005, 0.01, and 0.05 mg/kg. The developed method enables the multiresidue analysis of 12 ionic pesticides and relevant metabolites in a single analysis. Until now, the analysis of these compounds required several different single-residue methods using different chromatographic conditions. This multiresidue approach offers the possibility of more cost-effective and more efficient monitoring of polar ionic pesticides and contaminants that are of concern to food regulation bodies and consumers.

Analysis and Exposure Assessment of Perchlorate in Korean Dairy Products with LC-MS/MS

OBJECTIVES

Perchlorate is an emerging contaminant that is found everywhere, including various foods. Perchlorate is known to disturb the production of thyroid hormones and leads to mental disorders in fetuses and infants, as well as metabolic problems in adults. In this study, we attempted to establish an LC-MS/MS method for measuring perchlorate in dairy products and used this developed method to investigate perchlorate levels in Korean milk and yogurt samples.

METHODS

The developed method of perchlorate analysis requires a shaker and 1% acetic acid/acetonitrile as the extracting solvent. Briefly, the samples were extracted and then centrifuged (4000 rpm, 1hour), and the supernatant was then passed through a Envi™ Carb SPE cartridge that had been prewashed sequentially with 6 mL of acetonitrile and 6 mL of 1% acetic acid in water. The final volume of the sample extract was adjusted to 40 mL with reagent water and the final sample was filtered through a 0.20-µm pore size PTFE (Polytetrafluoroethylene) syringe filter prior to LC-MS/MS.

RESULTS

The average levels of perchlorate in milk and yogurt samples were 5.63 ± 3.49 µg/L and 3.65 ± 2.42 µg/L, respectively. The perchlorate levels observed in milk samples in this study were similar to those reported from China, Japan, and the United States.

CONCLUSIONS

The exposure of Koreans to perchlorate through the consumption of dairy products was calculated based on the results of this study. For all age groups, the calculated exposure to perchlorate was below the reference of dose (0.7 µg/kg-day) proposed by the National Academy of Science, USA, but the perchlorate exposure of children was higher than that of adults. Therefore, further investigation of perchlorate in other food samples is needed to enable a more exact assessment of exposure of children to perchlorate.