Determination of As, Bi, Cd, Co, Cr, Ga, In, Mn, Ni, Pb, Sb, Se, Sn, Te, Tl, and V in antihypertensive drugs by inductively coupled plasma mass spectrometry

A rapid procedure for the determination of As-75, Cd-114, 59Co Mn-55 Ni-58 V-51, Sn-120 Sb-123 Bi-209 Ga-69 In-115 Se-78 Te-130 Tl-205 Pb-208 and Cr-52 in antihypertensive drugs by inductively coupled plasma mass spectrometry (ICP-MS) is proposed. For these determinations the samples were prepared by a simple, fast extraction method with concentrated nitric acid. The optimization of plasma conditions, such as radiofrequency (RF) and nebulization gas flow rate, according to the manufacturer, was compared to a multivariate design (MD) optimization. The values obtained for the slopes and the correlation coefficients in the MD for all studied isotopes showed that the central point (1000 W and 1.0 L min(-1)) was the best condition and very close to the ones obtained in the optimization recommended by the manufacturer; therefore the following studies were made using the latter optimization. Calibration was performed by matrix matching with an r(2) higher than 0.99 for all isotopes investigated. The limits of detection and quantification ranged from 0.01 to 1.41 mu g L-1 for Tl-205 and Bi-209, and from 0.03 and 4.69 mu g L-1 for Se-78. Intra-assay studies (n=7 for each level) on the samples spiked with 0.1, 5.0, and 20.0 mu g L-1 of the isotopes of interest showed a coefficient of variation ranging from 0.3% to 10.9%. Recovery studies on the drug spiked with four levels (0.1, 2.0, 5.0, and 20.0 mu g L-1; n=3 for each level) showed recoveries between 96.5 +/- 1.6% and 115.5 +/- 7.5%. Seventy antihypertensive drug samples were analyzed and the results range from 0.03 to 4087.6 ng per capsule or tablet.