Determination of Five Elements in Mingmu Shangqing Tablets by ICP-MS
Objective To establish an inductively coupled plasma-mass spectrometry(ICP-MS)method for determining the contents of five elements in Mingmu Shangqing Tablets.Methods The samples were pretreated by a microwave digestion instrument.The plasma radio frequency power was 1550 W,the sampling depth was 8.0 mm,the plasma gas flow rate was 15 L/min,the atomization gas flow rate was 1.0 L/min,the auxiliary gas flow rate was 0.9 L/min,and the peristaltic pump speed was 0.1 r/s.Results The linear ranges of lead(Pb),cadmium(Cd),arsenic(As),mercury(Hg)and copper(Cu)were 4-100ng/mL,0.2-5ng/mL,2-50ng/mL,0.2-5ng/mL,20-500ng/mL(R2>0.9995,n=6)respectively.The RSDs of precision and repeatability tests were lower than 4.0%.The average recovery rates of the above five elements were 91.97%,104.12%,107.05%,92.74%,103.46%respectively,with RSDs lower than 4.0%(n=6).Pb,Cd,As,Hg and Cu were detected in 34 batches of samples from four manufacturing enterprises,with concentrations of 0.21-2.64,0.03-0.16,0.20-12.14,0.00-1.14,2.33-6.21 mg/kg respectively.According to the proposed limits(1.6,1.0,3.8,0.7,625 mg/kg),the element contents of two batches of samples(involving two manufacturing enterprises)were over the limit,with a disqualification rate of 5.88%.Conclusion The established method is simple,fast,sensitive and accurate,which is suitable for the determination of the five elements in Mingmu Shangqing Tablets.