Accurate Determination of Sulphur Content in Sediments by Double Focusing Inductively Coupled Plasma Mass Spectrometry Combined with Microwave Digestion and Studies on Related Matrix Effect

Abstract

Abstract A robust method for measuring sulphur content in sediments was established using double focusing inductively coupled plasma mass spectrometry at medium resolution combined with microwave digestion technique. The capability of Standard curve method (SCM) and Standard addition method (SAM) using Rh as internal standard was compared in correction of the matrix effect. The results showed that the matrix effect was not suppressed by SCM, but was effectively eliminated by SAM with drawback of low sample throughout. Therefore, the Standard addition calibration method (SACM) was creatively proposed in this study, which could simply and easily correct the matrix effect as the matrix content of sample and standard solution was matched within ±50%. The detection limit and liner range of this method were proved to be 0.5 mg kg −1 and 3.0–1000 μg L −1 , respectively, with spiked recovery of 95.8%-99.2%. Four sediment standard reference materials GBW07306, GBW07309, GBW07313 and SRM1646a were measured repetitively with the obtained sulphur contents of (853 ± 14) μg g −1 (2σ, n = 12), (181 ± 7) μg g −1 (2σ, n = 9), (3131 ± 52) μg g −1 (2σ, n = 12) and (3543 ± 70) μg g −1 (2σ, n = 9), respectively. The relative error of the four reference materials was +8.8%, +13.3%, +1.0% and +0.7%, respectively, with precision (RSD) less than 2%. This method was applied to measure the sulphur content in the sediment cores collected in the Yangtze Estuary and Hangzhou Bay. This proposed method was demonstrated as an accurate and rapid way of determining sulphur content in great batch of sediment samples, and has a broad application range including soil samples.