Two Microwave Digestion Pretreatment Methods for Determination of Heavy Metals in Vegetable Samples
-
摘要: 微波消解法是处理生物样品的主要技术,但存在处理效率不高等问题还有待进一步研究。本文采用高压低通量(12位)和低压高通量(41位)微波消解法对蔬菜样品进行前处理,电感耦合等离子体质谱法(ICP-MS)测定砷、镉、铬、铜、镍、铅和锌,氢化物发生-冷原子荧光光谱法(HG-CAFS)测定汞。采用两种前处理方法消解标准物质GBW 10010(大米)和GBW 10014(圆白菜),ICP-MS的测定值与标准值基本吻合,全流程加标回收率为91.5%~103.8%;用于测定GBW 10010和GBW 10014,因GBW 10010中铬、铅、砷,GBW 10014中砷的含量较低,测定值与标准值的相对误差较大;其余元素的测定值与标准值基本相符,表明两种前处理方法均能满足分析要求。但在保证测定结果质量的前提下,低压高通量微波消解处理样品,试剂用量少,单次样品处理量大,更加适合大批量生物样品的前处理。
-
关键词:
- 蔬菜样品 /
- 重金属元素 /
- 高压低通量微波消解 /
- 低压高通量微波消解 /
- 电感耦合等离子体质谱法 /
- 氢化物发生-冷原子荧光光谱法
Abstract: Microwave digestion technology is a relatively recent method for processing biological samples, but there are some problems, such as low efficiency, which require further study. As described in this paper, vegetables were decomposed by two different microwave digestion methods of high pressure low flux and low pressure high flux microwave digestion. The contents of As, Cd, Cr, Cu, Ni, Pb and Zn in the sample solutions were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), and contents of Hg by Hydride Generation-Cold Atomic Fluorescence Spectrometry (HG-CAFS). As shown by the experimental results, the measured value of National Standard Reference Materials is in agreement with the certified values by the two different methods. The relative errors of the two methods were less than 21%, the relative standard deviation was less than 4% and the recovery ratios were 91.5%-103.8%. Low pressure high flux microwave digestion method is a better method of sample dissolution for large quantities of biological sample analysis because it improves the efficiency of sample digestion. -
-
表 1 微波消解程序
Table 1 Procedures of microwave digestion
步骤 消解时间t/min 消解功率P/W 消解温度θ/℃ 高压 低压 高压 低压 高压 低压 1 10(升温) 10(升温) 1500 1500 120 120 2 5(保温) 5(保温) 1500 1500 120 120 3 5(升温) 10(升温) 1500 1500 160 150 4 10(保温) 5(保温) 1500 1500 160 150 5 5(升温) 10(升温) 1500 1500 200 175 6 20(保温) 20(保温) 1500 1500 200 175 表 2 线性范围、线性回归方程及相关系数
Table 2 Linearity ranges,linear regression equations and correlation coefficients
元素 线性方程 相关系数 线性范围
ρB/(μg·L-1)Cr y=4.8947×103x 0.9999 0~100 Ni y=1.7185×103x 0.9999 0~100 Cu y=4.2695×103x 1.0000 0~100 Zn y=0.9184×103x 0.9999 0~100 As y=0.9588×103x 0.9999 0~100 Cd y=3.0284×103x 0.9999 0~100 Pb y=9.7697×103x 0.9999 0~100 Hg y=1.2385×103x-14.059 0.9995 0~1.00 表 3 加标回收试验
Table 3 Recovery test of the method
元素 高压低通量微波消解法 低压高通量微波消解法 加标前
ρB/(μg·L-1)加标浓度
ρB/(μg·L-1)加标后
ρB/(μg·L-1)回收率/% 加标前
ρB/(μg·L-1)加标浓度
ρB/(μg·L-1)加标后
ρB/(μg·L-1)回收率/% Cr 117.6 80.0 200.0 103.0 128.8 80.0 207.3 98.1 Ni 27.2 20.0 45.5 91.5 30.4 20.0 50.9 102.5 Cu 45.6 40.0 85.2 99.0 54.4 40.0 93.0 96.5 Zn 149.6 80.0 232.6 103.8 138.4 80.0 215.7 96.6 As 20.8 20.0 40.6 99.0 23.2 20.0 43.2 100.0 Cd 7.36 4.0 11.3 98.5 7.44 4.0 11.4 99.0 Pb 30.4 20.0 49.2 94.0 24.0 20.0 42.5 92.5 Hg 0.438 0.4 0.849 102.8 0.419 0.4 0.791 93.0 注: 测定时溶液浓度超过标准曲线的元素做适量稀释。 表 4 方法准确度和精密度
Table 4 Accuracy and precision tests of the elements
标准物质
编号元素 wB/(μg·g-1) RE/% RSD/% 标准值 高压
消解低压
消解高压
消解低压
消解高压
消解低压
消解GBW 10010
(大米)Cr (0.09) 0.04 0.03 -55.56 -66.67 3.25 2.45 Ni 0.27±0.02 0.27 0.26 0.00 -3.70 2.14 0.41 Cu 4.9±0.3 4.75 5.00 -3.06 2.04 1.21 0.74 Zn 23±2 21.0 21.5 -8.70 -6.52 1.65 1.12 As 0.102±0.008 0.097 0.101 -4.90 -0.98 2.34 2.34 Cd* 87±5 86.9 87.0 -0.11 0 0.21 0.26 Pb 0.08±0.03 0.09 0.08 12.50 0 1.56 2.15 Hg* 5.3±0.5 5.01 5.33 -5.47 0.57 1.20 0.25 GBW 10014
(圆白菜)Cr 1.8±0.3 1.77 1.79 -1.67 -0.56 2.15 1.21 Ni 0.93±0.10 0.92 0.94 -1.08 1.08 2.90 0.32 Cu 2.7±0.2 2.5 2.6 -7.41 -3.70 1.85 1.23 Zn 262 26.6 25.7 2.31 -1.15 1.53 1.03 As 0.062±0.014 0.075 0.062 20.97 0 2.65 2.52 Cd* 356 36.5 34.0 4.29 -2.86 0.16 0.21 Pb 0.19±0.03 0.18 0.18 -5.26 -5.26 0.81 2.69 Hg* 10.9±1.6 10.5 10.6 -3.67 -2.75 0.56 0.67 注: 带*元素单位为μg/kg,括号内的数据为参考值。 表 5 高压低通量和低压高通量消解法的测定结果
Table 5 Analytical results of the elements in vegetables with high pressure and low pressure microwave digestion methods
样品
编号消解方式 wB/(μg·g-1) w(Hg)/
(μg·kg-1)Cr Ni Cu Zn As Cd Pb 1 高压低通量 1.47 0.34 0.57 1.87 0.26 0.092 0.38 5.47 低压高通量 1.61 0.38 0.68 1.73 0.29 0.093 0.30 5.24 2 高压低通量 1.21 0.18 0.42 1.38 0.042 0.83 0.54 3.51 低压高通量 1.33 0.19 0.45 1.54 0.041 0.91 0.58 3.60 3 高压低通量 0.63 0.13 0.40 1.30 0.026 0.42 0.22 2.13 低压高通量 0.64 0.14 0.47 1.61 0.026 0.51 0.23 2.67 注:测定时溶液浓度超过标准曲线的元素进行适量稀释。 -
史贵涛,陈振楼,李海雯,王利,许世远.城市土壤重金属污染研究现状与趋势[J].环境监测管理与技术, 2006, 18(6): 9-12. http://www.cnki.com.cn/Article/CJFDTOTAL-HJJS200606002.htm Hu X F, Wu H X, Zhang G Y, Fang S Q, Wu C J. Impact of urbanization on Shanghai′s soil environmental quality [J].Pedosphere, 2004,14(2): 151-158.
乔爱香,曹磊,江冶,赵斌,汤志云.干法灰化和微波消解-电感耦合等离子体发射光谱法测定植物样品中22个主次量元素[J].岩矿测试, 2010, 29(1): 29-33. http://www.cnki.com.cn/Article/CJFDTOTAL-YKCS201001011.htm Malusiewicz H, Kopras M. Methods for improving the sensitivity in atom trapping flame atomic: Analytical scheme for the direct determination of trace elements in beer [J]. Journal of Analytical Atomic Spectrometry, 1997(12): 1287-1291.
管仕栓,杨明峰,刘丁伟,程传玲,汪文良,刘艳芳,姚二民.不同消解方法对卷烟烟丝及滤嘴中Mn和Cu含量的影响[J].湖北农业科学, 2011, 50(8): 1689-1692. http://www.cnki.com.cn/Article/CJFDTOTAL-HBNY201108061.htm 孙长霞,张美婷,刘海学.预处理方法对测定荠菜中金属元素含量的影响[J].食品研究与开发,2011,32(8): 62-64. http://www.cnki.com.cn/Article/CJFDTOTAL-SPYK201108019.htm Yaman M, Durak M, Bakirdere S. Comparison of dry, wet, and microwave ashing methods for the determination of Al, Zn and Fe in yogurt samples by atomic absorption spectrometry[J].Spectroscopy Letters, 2005, 38(4-5): 405-417. doi: 10.1081/SL-200062997
潘钢,张勇,周磊,杨远航.测定川芎中有害金属元素的三种样品前处理方法的比较试验[J].理化检验:化学分册, 2010, 46(4): 404-406. http://www.cnki.com.cn/Article/CJFDTOTAL-LHJH201004026.htm 朱利中,戚文彬.微波消解技术在分析中的应用[J].冶金分析, 1995, 15(1): 25-33. http://www.cnki.com.cn/Article/CJFDTOTAL-SWJJ201605030.htm Wang H, Liu Y. The mineral content of Rhizoma cyperi after microwave-assisted digestion and determination by AAS [J].Spectroscopy Letters, 2010, 43(3): 149-154. doi: 10.1080/00387010903261222
田宝珍,曹福苍,雷鹏举,曲久辉.微波消解制样技术用于生物样品微量分析的研究[J].食品与发酵工业, 2000, 26(3): 15-20. http://www.cnki.com.cn/Article/CJFDTOTAL-SPFX200003005.htm 和丽忠,杜丽娟,严红梅,陈锦玉,黎其万.微波消解-电感耦合等离子体质谱法测定黑木耳中铅、镉、砷、铜、锌和铬[J].光谱实验室, 2012, 29(1): 435-438. http://www.cnki.com.cn/Article/CJFDTOTAL-GPSS201201135.htm 寇兴明,徐敏,顾永祚.微波消解/ICP-MS法测定川黄柏中微量重金属元素[J].光谱学与光谱分析,2007, 27(6): 1197-1200. http://www.cnki.com.cn/Article/CJFDTOTAL-GUAN200706042.htm Zhang H Y, Zheng Y, Hu H T, Qi J Y. Comparison of digestion methods for analysis of heavy metals in MSWI bottom ash [J].Key Engineering Materials,2011,10(474-476): 1075-1080.
肖振林,杨立红.高压微波消解-原子吸收光谱法测定葡萄中金属元素[J].江西农业学报,2010,22(4): 99-101. http://www.cnki.com.cn/Article/CJFDTOTAL-JXNY201004034.htm
计量
- 文章访问数: 1172
- HTML全文浏览量: 409
- PDF下载量: 17