ICP-MS在测定农药中重金属元素的应用
赵汝汝1 廖成朋2*
(1.重庆出入境检验检疫局技术中心,重庆,400020; 2.重庆港力环保股份有限公司,重庆,400016)
摘 要 目的 建立农药中铅、砷、镉、铬、镍、铜、锌七种金属元素的电感耦合等离子体质谱(ICP-MS)检测方法。方法 采用硝酸、双氧水、氢氟酸微波消解处理样品,用ICP-MS内标法测定七种重金属元素。结果 铅、砷、镉、铬、镍、铜、锌七种金属元素的检出限在0.02~0.18μg/L之间,样品回收率在95%~106%,方法精密度(RSD)为0.7%~3.9%。结论 方法简便、快速、准确,可作为农药中金属元素含量检测方法。Theapplication of ICP-MS in the determination of heavy metal elements inpesticides
ZHAO Ru-ru1 LIAO Cheng-peng2*
(1.Technical center of Chongqing entry exit inspection and Quarantine Bureau,Chongqing,40020,China ; 2. Chongqing Gangli environmental protectionLimited by Share Ltd, Chongqing, 400016)
Abstract Objective to establish an inductively coupled plasmamass spectrometry (ICP-MS) method for the determination of eight metals inlead, arsenic, cadmium, chromium, nickel, copper and zinc in pesticides.Methods the samples were treated by microwave digestion with nitric acid,hydrogen peroxide, hydrochloric acid and hydrofluoric acid, and seven metalelements were determined by ICP-MS internal standard method. Results thedetection limits of seven metal elements of lead, arsenic, cadmium, chromium, chromium,nickel, copper and zinc are between 0.02 and 0.18 μg/L, the recovery of samplesis from 95%to 106%, and themethod precision (RSD) is 0.7%to3.9%. Conclusionthe method is simple, rapid and accurate, and can be used for the determinationof metal elements in pesticides.表1 微波消解程序
Tab.1 microwave digestion procedure
步骤 | 功率/W | 温度/℃ | 升温时间/min | 维持时间/min |
1 | 1600 | 120 | 5 | 10 |
2 | 1600 | 160 | 10 | 15 |
3 | 1600 | 180 | 20 | 35 |
编号 | 消解体系/mL | ||
HNO3-H2O2 | HCl | HF | |
1 | 5 | 1 | — |
2 | 5 | — | 1 |
3 | 5 | 1 | 1 |
表3 各元素的线性范围、回归方程、相关系数和方法检出限
Tab.2 The linear range of each element, theregression equation, the correlation coefficient and the method detection limit
元素 | 线性范围/(μg.L-1) | 回归方程 | 相关系数 | 检出限/(μg.L-1) |
Pb | 0~200 | y=0.0002971X+0.0339234 | 0.9994 | 0.18 |
As | 0~200 | y=3.60443e-5X+0.0041156 | 0.9994 | 0.29 |
Cd | 0~200 | y=7.24685e-5X+0.00827459 | 0.9997 | 0.02 |
Cr | 0~200 | y=0.000129999X+0.0148435 | 0.9995 | 0.10 |
Cu | 0~200 | y=6.88151e-5X+0.00785744 | 0.9996 | 0.09 |
Zn | 0~200 | y=4.64713e-5X+0.00530618 | 0.9994 | 0.17 |
Ni | 0~200 | y=7.63085e-5X+0.00871305 | 0.9995 | 0.14 |
2.3回收率和精密度
在相同仪器条件下,对同一样品,测定本底值,同时取6份样品加入一定量的7种元素标准溶液,进行加标回收率及精密度实验,结果见表4。各元素加标回收率在95%~106%之间,方法相对标准偏差(RSD )在0.7%~3.9%之间。表4 回收率和精密度
Tab.3 Recovery and precision
元素 | 本底值/(μg.L-1) | 加入量/(μg.L-1) | 测定平均值/(μg.L-1) | 平均回收率/% | RSD/% |
Pb | 1.62 | 5.00 | 6.65 | 101 | 3.6 |
As | 59.4 | 50.0 | 107 | 95 | 3.9 |
Cd | 2.20 | 5.00 | 7.51 | 106 | 2.5 |
Cr | 745 | 400 | 1156 | 103 | 1.5 |
Cu | 1625 | 800 | 2427 | 100 | 0.7 |
Zn | 478 | 250 | 736 | 103 | 1.9 |
Ni | 82.4 | 50.0 | 133 | 101 | 2.8 |
2.4样品的测定
用建立的方法对市售5种农药样品中7种重金属进行测定,其结果见表5。表5 各品牌农药中重金属质量浓度
Tab.4 Recovery and precision
样品名称 | 元素/(μg.L-1) | ||||||
Pb | As | Cd | Cr | Cu | Zn | Ni | |
66.5%霜霉威盐酸盐水剂 | 1.62 | 59.4 | 2.20 | 745 | 1625 | 478 | 82.4 |
0.5%香菇多半糖水剂 | 721 | 65.6 | 1.42 | 884 | 2105 | 870 | 87.4 |
4%赤霉酸A3水剂 | 150 | 106 | 11.6 | 1 350 | 993 | 3 165 | 130 |
80%波尔多液 | 21 450 | 2 615 | 211 | 6 730 | 5.00e+7 | 3.14e+5 | 49 500 |
57.6%氯化铜粒剂 | 4 335 | 1 030 | 53 | 2 165 | 2.21e+5 | 53 750 | 2 230 |
8%宁南霉素水剂 | 39.3 | 65.5 | 9.94 | 335 | 1.76e+5 | 4 015 | 1 195 |