Method development and validation of simultaneous determination of seventeen metals in water by ICP/MS

Abstract

A simple, precise, accurate, and sensitive method is developed and validated for simultaneous determination of seventeen metals (Li, Sr, Ba, Tl, Pb, Bi, Al, K, Cr, Mn, Co, Ni, Cu, Zn, Mo, Ag, and Cd) in water by ICP-MS. The optimum conditions of the ICP-MS are as follows: nebulizer gas (argon) flow rate: 0.9 L/min, auxiliary gas (argon) flow 0.3 L/min, plasma (argon) gas flow: 15 L/min, reaction gas flow (helium) 4mL/min. This method is validated according to the requirements for new methods, which include linearity and range, accuracy, precision, selectivity, limit of detection (LOD), and limit of quntitation (LOQ). The current method demonstrates good linearity over the range of 1-1000 ppb with r² greater than 0.999 for the seventeen metals. The recovery of the metals from water samples ranges from 97.5 to 101.7%. The method is selective where minimal interferences between the metals is observed (CeO/Ce = 1%, and Ce⁺²/Ce⁺¹ = 1%), and with good resolution (0.8 amu at 10% height). The method is also precise where the RSD of the responses (cps) of replicates of the metals at three concentration levels is less than 1%. Low LOD and LOQ of metals using this method enable the detection and quantitation of these metals at low concentrations. Real water samples from West Bank in Palestine (groundwater) were analyzed for their trace metals content using this method.