Use of the Hildebrand grid nebuliser for analysis of high matrix solutions containing easily ionisable elements with inductively coupled plasma mass spectrometry

Abstract

Aqueous, high dissolved salt solutions and biological fluids (urine) were introduced with the Hildebrand grid nebuliser for inductively coupled plasma mass spectrometry (ICP-MS) detection. Optimisation studies of ICP power, plasma sampling position and nebuliser gas flow-rate were performed. Three-dimensional plots that show optimum system performance were obtained at a plasma sampling position of 12 mm, ICP power of range 1.35–1.50 kW and a nebuliser gas flow of 0.65 l min^–1. These results are similar to previously reported data. Ionisation suppression as a function of synthetic ocean water (SOW) and urine concentration was studied. A 10% analyte suppression (Co, In, Ba, Pb) generally occurred for a 0.01–0.10 M SOW solution. The ionisation suppression for a 100% urine matrix is approximately 40%(Co, As, Cd, Ba, Pb). Detection limits for SOW were degraded by up to one and a half orders of magnitude. For the urine matrix, detection limits were degraded 15–40% for the elements studied.