ICP-AES测定工作场所空气中镉、铬、锰、镍、铅的干扰校正

Interference correction for determination of cadmium,chromium,manganese,nickel and lead in workplace air by ICP-AES

目的探讨电感耦合等离子体-原子发射光谱(ICP-AES)法测定工作场所空气中镉、铬、锰、镍、铅浓度时减少干扰的校正方法。方法分析ICP-AES法测定工作场所空气中镉、铬、锰、镍、铅的干扰来源,比较背景扣除和内标校正前后的测定结果;以干扰误差对干扰元素质量浓度进行线性回归,得到干扰因子表;采用背景扣除、内标校正和干扰因子法校正实际样品测定结果。结果未扣除背景的镉和铅测定结果与理论值相对偏差达219.5%和131.5%,而扣除背景后的测定值与理论值相对偏差均<10.0%;当溶液中总金属离子质量浓度>800.00 mg/L时,未加内标的测定结果与理论值相对偏差为-21.0%～-11.0%,内标校正后相对偏差均<10.0%。采用本方法校正焊接烟尘中的5种金属的质量浓度,镉干扰校正前、后质量浓度分别为3.90～32.50和1.20～7.10μg/L;镍干扰校正前、后质量浓度分别为111.00～1 220.00和99.00～1 120.00μg/L;铬、锰、铅干扰校正前、后质量浓度不变。结论 ICP-AES法测定工作场所空气中金属时采用背景扣除、内标校正、干扰因子表等方法进行干扰校正可较好地排除干扰,保证结果准确性。

Objective To explore the interference correction reduction method for the determination of cadmium(Cd), chromium(Cr), manganese(Mn), nickel(Ni) and lead(Pb) concentration in workplace air by inductively coupled plasma-atomic emission spectrometry(ICP-AES). Methods The interference sources in the determination of metals in workplace air with ICP-AES was analyzed. The results before and after the background correction or the internal standard calibration were compared. Linear regression is performed on the interference element mass concentration by interference error to obtain a table of interference factors. The measurement results of actual samples were corrected using background subtraction, internal standard correction, and interference factor method. Results The relative deviation of results and theoretical values without background subtraction were 219.5% and 131.5% for Cd and Pb, respectively. The relative deviation between the measured values and theoretical values was less than 10.0% after background subtraction. When the total metal ion concentration was >800.00 mg/L, the relative deviation between measured result and the theoretical values was-21.0%--11.0% without internal standard correction, and the absolute value of them were less than 10.0% after internal standard correction. The interference correction method was used to correct the concentration of Cd, Cr, Mn, Ni, Pb in welding smoke. The mass concentrations of Cd before and after interference correction were 3.90-32.50 and 1.20-7.10 μg/L, respectively. The mass concentrations of nickel before and after interference correction were 111.00-1 220.00 and 99.00-1 120.00 μg/L, respectively. The mass concentration of Cr,Mn and Pb remained unchanged before and after the interference correction. Conclusion The background correction, internal standard correction and interference factor table can eliminate the interference for determination of metals in workplace air by ICP-AES and ensure the accuracy of results.