Sample analysis by on-line isotope dilution inductively coupled plasma mass spectrometry

Abstract

An on-line isotope dilution technique is developed by coupling commercial flow injection instruments with an inductively coupled plasma mass spectrometer. Application of the technique is demonstrated by the determination of lead concentrations in diverse standard reference materials. The precision of the method, using optimum sample to spike ratios and a steady-state merging stream, is better than 1 % . The approach simplifies sample preparation and analysis, and matrix effects have no influence on the determinations.

Validation of total inorganic element determination in wastewater samples by on-line isotope dilution inductively coupled plasma mass spectrometry

“…8 In ICP techniques, the analytical response, mainly, depends on the element amount in the plasma. The online isotope dilution concept was rst introduced by Lasztity et al in 1989 for elemental analysis.…”

Online isotope dilution and inductively coupled plasma mass spectrometry: from elemental to species quantification

“…The multiple injection modes produced transient signals in the spiked samples, covering a wide analyte concentration range. 2,3 This application emphasized the effect of nebulizer flow rate, measurement period and dwell times, along transient signals for isotope ratio (IR) measurements. 3 Klinkenberg et al 22 presented in 1993 a simplified flow scheme to perform time controlled injection of discrete volumes of sample or calibration standard into a continuous flowing isotopic enriched solution.…”

“…Considering that sample and spike solutions are introduced into the system with identical flow rates, the time during which the valves remain switched on establishes the volume introduced. Under this condition the ID equation was modified to: (2) Where: R b = isotope measured in the mixture corrected for mass discrimination, C S and C Sp = analyte concentration in the sample and enriched solution, A S , B S and A Sp , B Sp = sample and spike isotope abundances. The time delay for introducing the sample was t S and the time delay for the spike was t Sp .…”

“…2,3 The online ID was performed by continuously pumping sample and spike solutions through separated streams merged in a T-device before reaching the ICP-MS nebulizer. FI and other continuous flow systems have been largely used for online ICP-IDMS (Table 1).…”

“…1 in different applications. 2,3 The most common proposal to perform online FI-ID applications involves the introduction of both, sample and isotopic enriched spike, in different channels and the continuous merging of both in a T-junction before introduction into the plasma. The ICP-MS equipments are able to measure at least two isotopes free from interferences for many elements.…”