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.

中文翻译：

---

亲水相互作用色谱-串联质谱法准确，灵敏，快速地测定茶叶中的高氯酸盐。

高氯酸盐是一种环境污染物，会中断甲状腺激素的产生，最近茶中的高氯酸盐引起了广泛关注。在这项研究中，开发了一种使用亲水相互作用色谱-串联质谱法和简化的QuEChERS程序测定茶叶中高氯酸盐的准确方法。该方法利用两性离子HILIC色谱柱进行分离，最佳的梯度洗脱液由乙腈和含0.1％甲酸和20 mmol L ^-1甲酸铵的水溶液组成。校准曲线由二次模型拟合为1 / x权重而不是线性模型。当使用乙腈或甲醇作为提取溶剂时，高氯酸盐只能部分提取，因此选择乙腈/水（1：1，v / v）从茶叶样品中提取高氯酸盐。石墨化炭黑被用作分散固相萃取吸附剂，以净化茶提取物。该方法显示出令人满意的准确性，绿茶和红茶的回收率为81.4–100.9％，相对标准偏差为1.3–14.5％。定量限为0.005 mg kg ^-1，而检出限为绿茶为0.0011 mg kg ^-1和0.0013 mg kg ^-1对于红茶，表明该方法具有极好的灵敏度。在100个真实茶样品中发现高氯酸盐的阳性率为100％，浓度范围为0.0030 mg kg ^-1至0.78 mg kg ^-1。这种准确，灵敏和快速的方法将适用于监测，风险评估和茶叶中高氯酸盐的来源鉴定。