Abstract This paper proposes a rapid method for the simultaneous determination of nitrate, nitrite and thiocyanate in different milk samples (cow, goat and soy) using capillary zone electrophoresis. The separations were conducted in a fused silica capillary dynamically coated with quaternary ammonium chitosan, with a total length of 48.5 cm (40 cm effective x 75 μm internal diameter) and direct detection in the UV region at 210 nm. The background electrolyte (BGE) was composed of 30 mmol L−1 of aminocaproic acid and 24 mmol L1 of perchloric acid (pH 3.85).A typical anodic electroosmotic flow of -31 × 10-9 m2 V−1 s−1 was observed at the pH of the separations. Bromate was used as the internal standard. The samples were injected by hydrodynamic pressure (50 mbar, 40 s) and the separation voltage was −30 kV. The proposed method was validated and presented good linearity (R2> 0.99) in the linear range of 0.1–4.0 mg L−1. The ranges of the limit of detection (LOD) and limit of quantification (LOQ) were 0.03-0.04 and 0.05–0.07 mg L−1, respectively. The intra-day and inter-day precision values were better than 4.2 and 8.7 %, respectively. Recovery values ranged from 85 to 104% for the different samples of milk. The proposed method was applied in 12 commercial samples with run times of less than 2 min. The good analytical performance indicates that the method proposed is a promising alternative for the determination of nitrate, thiocyanate and nitrite in milk samples.

中文翻译：

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一种以壳聚糖季铵盐为电渗流逆变器的CZE-UV快速同时测定牛奶中硝酸盐、亚硝酸盐和硫氰酸盐的方法

摘要 本文提出了一种使用毛细管区带电泳同时测定不同牛奶样品（牛、山羊和大豆）中硝酸盐、亚硝酸盐和硫氰酸盐的快速方法。分离是在动态涂有季铵壳聚糖的熔融石英毛细管中进行的，总长度为 48.5 cm（40 cm 有效 x 75 μm 内径），并在 210 nm 的 UV 区域直接检测。背景电解质 (BGE) 由 30 mmol L-1 氨基己酸和 24 mmol L1 高氯酸 (pH 3.85) 组成。 观察到典型的阳极电渗流为 -31 × 10-9 m2 V-1 s-1在分离的 pH 值。溴酸盐用作内标。样品通过流体动压（50 mbar，40 s）进样，分离电压为-30 kV。所提出的方法经过验证并在 0.1–4.0 mg L-1 的线性范围内呈现出良好的线性 (R2> 0.99)。检测限 (LOD) 和定量限 (LOQ) 的范围分别为 0.03-0.04 和 0.05-0.07 mg L-1。日内和日间精度值分别优于 4.2% 和 8.7%。不同牛奶样品的回收率范围为 85% 至 104%。所提出的方法应用于 12 个商业样品，运行时间少于 2 分钟。良好的分析性能表明，所提出的方法是测定牛奶样品中硝酸盐、硫氰酸盐和亚硝酸盐的一种有前景的替代方法。分别。日内和日间精度值分别优于 4.2% 和 8.7%。不同牛奶样品的回收率范围为 85% 至 104%。所提出的方法应用于 12 个商业样品，运行时间少于 2 分钟。良好的分析性能表明，所提出的方法是测定牛奶样品中硝酸盐、硫氰酸盐和亚硝酸盐的一种有前景的替代方法。分别。日内和日间精度值分别优于 4.2% 和 8.7%。不同牛奶样品的回收率范围为 85% 至 104%。所提出的方法应用于 12 个商业样品，运行时间少于 2 分钟。良好的分析性能表明，所提出的方法是测定牛奶样品中硝酸盐、硫氰酸盐和亚硝酸盐的一种有前景的替代方法。