A selective, sensitive and useful method, based on modified QuEChERS cleanup combined with liquid chromatography-tandem mass spectrometry (LC–MS/MS) in the negative-ion electrospray ionization (ESI⁻) mode, was developed and validated for the simultaneous determination of three inorganic anions including perchlorate (ClO₄⁻), bromate (BrO₃⁻) and hypophosphite (H₂PO₂⁻) in flour. The extraction parameters and LC–MS/MS conditions were optimized by single-factor experiment and sorbent combination in modified QuEChERS clean-up was optimized through response surface analysis. Three target analytes were separated on a normal-phase Phenomenex Luna Silica (2) column (150 mm × 2.0 mm, 5 μm, 100 Å) with the mobile phase of a mixture of 5 mmol/L ammonium acetate water solution and acetonitrile, detected by MS/MS under multiple reaction monitoring and quantified by external standard method. The developed method was validated in terms of the sensitivity, linearity, accuracy and precision, and matrix effect. The method showed a good linearity (R² > 0.999) for all analytes in their respective concentration ranges. The ILOQs and MLOQs for perchlorate, bromate and hypophosphite were 0.1, 0.5, 5.0 μg/L and 2.0, 6.0, 60.0 μg/L, respectively. The average recoveries of three target analytes from the negative samples spiked at three different concentrations were in a range from 84.6% to 104.9%. The intra-day precision (n = 6) and inter-day precision (n = 5) of the target analytes were in the ranges of 2.9%–6.9% and 6.4%–8.2%. The matrix effect of this method was observed between 0.83 and 1.17 and was acceptable. The validated method was successfully applied to determine the concentrations of these inorganic anions in flour. Results found that perchlorate and hypophosphite were detected in 33 out of 50 and 7 out of 50 flour samples.

选择性，灵敏的和有用的方法，基于改性的QuEChERS清理与负离子电喷雾离子化（ESI液相色谱-串联质谱（LC-MS / MS）结合^- ）模式，被开发并验证了同时测定3个无机阴离子包括高氯酸根（CLO ₄ ^- ），溴（BRO ₃ ^- ）和次（H ₂ PO ₂ ^-）面粉中。通过单因素实验优化了萃取参数和LC-MS / MS条件，并通过响应表面分析优化了改良QuEChERS净化过程中的吸附剂组合。在正相Phenomenex Luna硅胶（2）色谱柱（150 mm×2.0 mm，5μm，100Å）上分离出三种目标分析物，流动相为5 mmol / L乙酸铵水溶液和乙腈的混合物通过MS / MS在多反应监测下进行，并通过外标方法进行定量。所开发的方法在灵敏度，线性，准确度和精密度以及基质效应方面得到了验证。该方法显示出良好的线性（R ² > 0.999）的所有浓度在其各自的浓度范围内的所有分析物。高氯酸盐，溴酸盐和次磷酸盐的ILOQ和MLOQ分别为0.1、0.5、5.0μg/ L和2.0、6.0、60.0μg/ L。从以三种不同浓度加标的阴性样品中三种目标分析物的平均回收率在84.6％至104.9％的范围内。 目标分析物的日内精度（n  = 6）和日间精度（n = 5）在2.9％–6.9％和6.4％–8.2％的范围内。观察到该方法的基质效应在0.83至1.17之间，并且是可以接受的。验证的方法已成功应用于测定面粉中这些无机阴离子的浓度。结果发现，在50个面粉样品中有33个和50个面粉样品中有7个检测到了高氯酸盐和次磷酸盐。