【仪电分析】生活饮用水中元素分析 石墨炉原子吸收解决方案

【仪电分析】生活饮用水中元素分析石墨炉原子吸收解决方案本方案参考GB/T 5750.6-2023《生活饮用水标准检验方法 第6部分:金属和类金属指标》，用石墨炉原子吸收分光光度法进行测定生活饮用水中银、钡、镉、钴、铜、钼、镍、铅、铊、钒的含量，此方法适用于生活饮用水和水源水中银、钡、镉、钴、铜、钼、镍、铅、铊、钒的测定。1、 主要仪器和试剂1.1  4730FG原子吸收分光光度计；1.2  空心阴极灯：银、钡、镉、钴、铜、钼、镍、铅、铊、钒；1.3  天平：万分之一；1.4  硝酸：优级纯；1.5  标准溶液银、钡、镉、钴、铜、钼、镍、铅、铊、钒单元素溶液标准物质：ρ =1g/L；1.6  实验室常规玻璃器皿。2、 实验条件2.1 银、钡、镉、钴、铜、钼、镍、铅、铊、钒石墨炉实验参数表1 石墨炉法实验参数元素波长（nm）狭缝（nm）灯电流（mA）背景校正方式银（Ag）328.10.22.5氘灯钡（Ba）553.60.111.0无镉（Cd）228.80.22.5氘灯钴（Co）240.70.23.5氘灯铜（Cu）324.70.22.5氘灯钼（Mo）313.30.25.0氘灯镍（Ni）232.00.22.5氘灯铅（Pb）283.30.22.5氘灯铊（Ti）276.90.22.5氘灯钒（V）318.40.15.0氘灯三、实验方法3.1 标准曲线绘制铜标准使用溶液 [ρ(Cu)=1μg/mL]：取铜单元素溶液标准物质0.1mL于100mL容量瓶中，用1+99硝酸稀释至刻度。取6支100mL容量瓶，分别移取铜标准使用溶液0mL、0.5mL、1.0mL、2.0mL、3.0mL和4.0mL于容量瓶中。用1+99硝酸稀释至刻度，摇匀。此标准系列相当于含铜0ng/mL、5.0ng/mL、10ng/mL、20ng/mL、30ng/mL、40ng/mL。银、钡、镉、钴、钼、镍、铅、铊、钒依据上述步骤依次配制，标准曲线梯度点如表2所示。在最佳分析条件下进行测试，测定标准曲线系列。表2 石墨炉法测定各元素标准曲线配制表元素STD-1ng/mLSTD-2ng/mLSTD-3ng/mLSTD-4ng/mLSTD-5ng/mLSTD-6ng/mLSTD-7ng/mLSTD-8ng/mLSTD-9ng/mL银（Ag）02.55.0102030///钡（Ba）01020406080///镉（Cd）00.51.03.05.07.0///钴（Co）05.010203040///铜（Cu）05.010203040///钼（Mo）05.010203040///镍（Ni）05.0102030////铅（Pb）02.55.010203040//铊（Ti）00.51.02.05.010204050钒（V）010203040////4、 实验结果4.1 标准曲线将仪器调至最佳分析条件下进行测试，银、钡、镉、钴、铜、钼、镍、铅、铊、钒各元素标准曲线如表3所示。表3 石墨炉法测定各元素标准曲线表元素检测方法线性方程相关系数银（Ag）石墨炉法A=0.0213C+0.0081R=0.9995钡（Ba）石墨炉法A=0.0030C-0.0011R=0.9998镉（Cd）石墨炉法A=0.0516C+0.0015R=0.9999钴（Co）石墨炉法A=0.0080C-0.0014R=0.9997铜（Cu）石墨炉法A=0.0065C+0.0086R=1.0000钼（Mo）石墨炉法A=0.0075C+0.0026R=0.9996镍（Ni）石墨炉法A=0.0091C-0.0010R=0.9999铅（Pb）石墨炉法A=0.0059C+0.0038R=0.9996铊（Ti）石墨炉法A=0.0072C+0.0006R=0.9998钒（V）石墨炉法A=0.0018C+0.0037R=0.9998 4.2 检出限测试以1+99硝酸纯水为空白试样，按3.2中样品预处理后进行测试。银、钡、镉、钴、铜、钼、镍、铅、铊、钒各元素检出限如表4。表4 银、钡、镉、钴、铜、钼、镍、铅、铊、钒检出限元素标准偏差SD（n=11）斜率（k）检出限(ng/mL)银（Ag）0.00020.02130.03钡（Ba）0.00070.00300.70镉（Cd）0.00040.05160.02钴（Co）0.00100.00800.38铜（Cu）0.00070.00650.32钼（Mo）0.00110.00750.44镍（Ni）0.00060.00910.20铅（Pb）0.00030.00590.15铊（Ti）0.00050.00720.21钒（V）0.00040.00180.674.3 精密度实验以超纯水为空白进行加标实验，对加标浓度为银、镉5ng/mL；钴、铜、钼、铅、钒30ng/mL；钡60ng/mL；镍20ng/mL；铊40ng/mL的标准溶液进行7次测定，精密度结果如表5。表5 石墨炉法测定各元素精密度实验元素水样测试结果（ng/mL）均值ng/mLSDng/mLRSD%1234567银（Ag）4.925.044.965.165.144.844.985.010.1172.34钡（Ba）61.361.460.960.760.560.161.961.00.5920.97镉（Cd）5.085.115.025.094.924.945.005.020.0741.48钴（Co）29.830.630.630.930.329.729.530.20.5151.70铜（Cu）30.831.131.031.331.130.931.131.10.1630.52钼（Mo）28.930.130.931.229.728.430.029.90.9743.26镍（Ni）19.819.819.320.119.719.019.819.60.3821.95铅（Pb）28.529.129.128.528.528.630.729.00.8112.80铊（Ti）38.339.839.939.839.940.441.540.00.9532.38钒（V）30.330.330.531.429.929.630.130.30.5531.824.4 回收率验证以超纯水为空白进行加标实验，分别对高、低浓度的加标水样进行测试，高、低浓度的加标回收率实验结果如表6、7。表6 低标回收率实验元素水样加标测试结果（ng/mL）均值ng/mL理论值ng/mL回收率(%)1234567银（Ag）4.925.044.965.165.144.844.985.015.00100钡（Ba）21.020.619.618.619.919.820.820.120.0100镉（Cd）1.010.970.980.961.080.9610.9920.9921.00099.2钴（Co）10.810.410.69.9110.210.310.310.410.0104铜（Cu）11.210.911.010.911.011.010.910.910.0109钼（Mo）10.610.89.219.779.669.579.659.8910.098.9镍（Ni）9.839.9610.29.739.7610.110.29.9710.099.7铅（Pb）4.984.704.644.645.025.125.304.915.0098.2铊（Ti）1.861.841.892.142.101.971.901.962.0098.0钒（V）19.719.918.719.020.122.120.720.020.0100表7 高标回收率实验元素水样加标测试结果（ng/mL）均值ng/mL理论值ng/mL回收率(%)1234567银（Ag）19.920.919.720.819.920.620.020.220.0101 钡（Ba）61.361.460.960.760.560.161.961.060.0102镉（Cd）5.085.115.025.094.924.945.005.035.00101钴（Co）29.830.630.630.930.329.729.530.230.0101铜（Cu）30.831.131.031.331.130.931.131.030.0103钼（Mo）28.930.130.931.229.728.430.029.930.099.7镍（Ni）19.819.819.320.119.719.019.819.620.098.0铅（Pb）28.529.129.128.528.528.630.729.030.096.7铊（Ti）38.339.839.939.839.940.441.540.040.0100钒（V）30.330.330.531.429.929.630.130.330.0101五、结论我们使用了上海仪电分析仪器有限公司的高灵敏度、高性能的4730FG原子吸收光谱仪，石墨炉法测定饮用水中的银、钡、镉、钴、铜、钼、镍、铅、铊、钒含量。本法具有操作简便，检测限低，重复性好，线性范围宽等特点,完全满足GB/T 5750.6-2023标准中相关测定要求。