In this study a procedure based on liquid chromatography (LC) and dynamic reaction cell inductively coupled plasma mass spectrometry (DRC ICP-MS), coupled with ultrasonic nebulization, for chromium speciation in rice was reported. Chromium (Cr) containing species, including Cr(III) and Cr(VI), were well separated by reversed phase HPLC with a C18 column as the stationary phase and a solution containing 0.5 mmol L⁻¹ tetrabutyl ammonium phosphate (TBAP), 0.1 mmol L⁻¹ EDTA and 2% (v/v) methanol (pH 6.9) as the mobile phase using isocratic elution. The chromatographic separation was complete in 4.5 min. Ammonia gas was employed as the reactive gas in the DRC to minimize spectral interference due to ⁴⁰Ar¹²C⁺ and ³⁵Cl¹⁶OH⁺ and ⁴⁰Ar¹³C⁺ and ³⁵Cl¹⁸O⁺ ions on the signal of ⁵²Cr⁺ and ⁵³Cr⁺, respectively. The detection limits were in the range 0.011–0.012 ng Cr mL⁻¹. To verify the accuracy, the developed procedure was applied on a certified reference material (NIST SRM 1573a Tomato Leaves) wherein the sum of the concentrations of individual species agreed with the total certified concentration of Cr. Species were extracted using microwave heating with 1% (v/v) HF and 2 mmol L⁻¹ EDTA. After ensuring the accuracy, this procedure has been applied to determine various Cr compounds present in rice and rice cereal. Supernatants were injected directly into the LC-ICP-MS system after dilution. The spike recovery was in the range of 95–105% and precision between sample replicates was better than 5% for all determinations. The LC-ICP-MS results showed satisfactory agreement with the total Cr concentrations obtained by ICP-MS analysis. Both Cr(III) and Cr(VI) were present in the samples analyzed. An unknown Cr compound was found in all the rice samples analyzed.

中文翻译：

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液相色谱-电感耦合等离子体质谱-超声雾化法测定水稻中的铬

在这项研究中，报道了一种基于液相色谱（LC）和动态反应池电感耦合等离子体质谱仪（DRC ICP-MS）以及超声雾化的方法，用于水稻中的铬形成。通过反相HPLC以C18色谱柱为固定相和含有0.5 mmol L ^-1磷酸四丁基铵（TBAP），0.1的溶液对含Cr（III）和Cr（VI）的铬（Cr）进行了很好的分离使用等度洗脱，将mmol L ^-1 EDTA和2％（v / v）甲醇（pH 6.9）作为流动相。色谱分离在4.5分钟内完成。氨气被用作DRC中的反应性气体，以最大程度地减少⁴⁰ Ar引起的光谱干扰在⁵² Cr ⁺和⁵³ Cr ⁺信号上分别显示¹² C ⁺和³⁵ Cl ¹⁶ OH ⁺和⁴⁰ Ar ¹³ C ⁺和³⁵ Cl ¹⁸ O ⁺离子。检出限范围为0.011-0.012 ng Cr mL ^-1。为了验证准确性，将开发的程序应用于经过认证的参考材料（NIST SRM 1573a番茄叶），其中各个物种的浓度之和与总的Cr认证浓度一致。使用具有1％（v / v）HF和2 mmol L ^-1 EDTA的微波加热提取物种。在确保准确性之后，该程序已用于确定大米和大米中存在的各种Cr化合物。稀释后将上清液直接注入LC-ICP-MS系统。所有测定的加标回收率均在95％至105％之间，并且样品重复之间的精密度优于5％。LC-ICP-MS结果与通过ICP-MS分析获得的总Cr浓度令人满意。Cr（III）和Cr（VI）存在于分析的样品中。在所有分析的大米样品中均发现了未知的Cr化合物。