糙米中砷形态检测方法的对比研究

目的比较液相色谱-原子荧光光谱法(highperformance liquid chromatography atomic fluorescence spectrometry,HPLC-AFS)和液相色谱-电感耦合等离子体质谱法(high performance liquid chromatography inductively coupled plasma mass spectrometry, HPLC-ICP-MS)两种方法对糙米中砷形态的测定。方法糙米样品经0.15 mol/L硝酸溶液提取,分别采用HPLC-AFS联用仪,流动相为15 mmol/L的磷酸二氢氨缓冲溶液(pH=6.0),经CNWSep AX阴离子交换色谱柱分离检测;同时,采用HPLC-ICP-MS联用仪,流动相为含5 mmol/L己烷磺酸钠、20 mmol/L柠檬酸的缓冲溶液(pH=4.3),经安捷伦ZorbaxSB-Aq反相色谱柱分离检测。结果两种方法检测4种砷形态在5.0～100.0 ng/mL范围内线性良好,相关系数均在0.999以上; HPLC-AFS法的检出限分别为2.3、0.6、1.0和1.1 ng/mL,加标回收率在85.1%～106%之间,相对标准偏差(relative standard deviation, RSD)均小于5%; HPLC-ICP-MS法的检出限分别为0.1、0.1、0.1和0.2 ng/mL,加标回收率在82.8%～106%之间,相对标准偏差(RSD)均小于5%。结论两种方法都可以满足糙米中4种砷形态的检测,在实际情况中可根据需要选择相应的检测方法。

Comparative study on the detection methods of arsenic in rice

Objective To compare the determination of arsenic species in brown rice by high performance liquid chromatography atomic fluorescence spectrometry (HPLC-AFS) and high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Methods Rice samples were extracted with 0.15 mol/L nitric acid solution and separated by HPLC-AFS with 15 mmol/L ammonia dihydrogen phosphate buffer solution (pH=6.0) as mobile phase, and determined by CNWSep AX anion exchange chromatography column. Meanwhile, the samples were separated by HPLC-ICP-MS with 5 mmol/L sodium hexane sulfonate and 20 mmol/L citric acid buffer solution (pH=4.3) as mobile phase, and determined by Agilent Zorbax SB-Aq reversed phase chromatography column. Results The linearity of the 2 methods was good in the range of 5.0?100.0 ng/mL, and the correlation coefficient was above 0.999. The detection limits of HPLC-AFS were 2.3, 0.6, 1.0 and 1.1 ng/mL, respectively, the recoveries were between 85.1% and 106%, and the relative standard deviation (RSD) was less than 5%. The detection limits of HPLC-ICP-MS were 0.1, 0.1, 0.1 and 0.2 ng/mL, respectively. The recoveries were between 82.8% and 106%, and the relative standard deviation (RSD) was less than 5%. Conclusion Both methods can satisfy the detection of 4 arsenic forms in rice, and the corresponding detection method can be selected according to needs in actual situations.