Study on the Availability of Wet Chemical Digestion of Geo-electrochemical Polyurethane Foam Samples

Abstract

As the pretreatment methods in analyzing geo-electrochemical polyurethane foam samples, ashing and microwave digestion methods are suitable for determination of most elements. Both methods have their disadvantages. The ashing method may cause volatilization loss of some elements (e.g. Hg, As) under high temperature, whereas issues about sample representation and detection limit exist in the microwave digestion method because of the small amount of sample (0.1 g). Wet chemical digestion is a traditional pretreatment method, which is widely used in the pretreatment of various geochemical samples and has the advantages of complete digestion, low element loss and good sample representation. However, because of the problems of explosion and acid blank during digestion of polyurethane foam (organic) samples, this method has not been used in pretreatment of geo-electrochemical foam samples. For this study a geo-electrochemical exploration line in Luokedun hydrothermal lead-zinc polymetallic deposit in Inner Mongolia was selected as the research subject. 20 mL of Nitric acid, 5 mL of perchloric acid, and 5 mL of aqua regia were used to digest 0.5 g foam samples. The contents of some related elements were determined by High-resolution Inductively Coupled Plasma-Mass Spectrometry (HR-ICP-MS) and Atomic Fluorescence Spectrometry (AFS). Results show that contents of the foam blank are relatively low for most elements, and the geochemical profiles show good anomalies. It is suggested that wet digestion is feasible in the analysis of geo-electrochemical polyurethane foam samples, and could be used widely in the future.

Keywords

• geo-electrochemistry
• polyurethane foam samples
• wet digestion
• hydride generation-atomic fluorescence spectrometry
• high-resolution inductively coupled plasma-mass spectrometry