Comparison of the Acid Combinations in Microwave-assisted Digestion of Marine Sediments for Heavy Metal Analyses

Abstract

Sediments as a tool for monitoring contamination by heavy metals in the environment has long been considered. It is therefore a necessity to produce reliable data for such purposes. Microwave-assisted acid dissolution has proved to be a suitable method for digesting complex matrices, such as sediments. However, due to the infancy of the technique, the procedures are numerous and varied in both the reagents used and microwave conditions. In this study, the efficiency of two recommended acid mixtures, a HNO3-HF mixture and an aqua regia-HF mixture, under the same microwave digestion conditions were compared using certified reference materials. It was observed that the HNO3-HF mixture showed better efficiency than the aqua regia-HF mixture in most of the heavy metals analyzed in all certified reference materials used.

The environmental impact of gold mines: pollution by heavy metals

“…ICP multi standards (1 and 2) were used to generate a calibration curve to quantify the samples. Microwave oven digestion has proved to be a suitable technique to digest samples with complex matrices [39] and was therefore used for digesting, soil samples and ashed plant samples. The soil sample, solid tailings and ashed plant samples were digested in teflon bombs using method EPA 3050B in a microwave oven (ETHOSEL, Milestone Microwave Stystem USA) with the following program; 8 min in phase one and 4 min in phase two at 200°C.…”

Comparative study on open system digestion and microwave assisted digestion methods for metal determination in shrimp sludge compost

“…The first application of microwaves for sample preparation was reported in 1975 [27]. Since that time many microwave assisted dissolution methods have been developed to include a variety of sample matrices such as soil [28], fish [29], sediments [30], sludge [31][32][33][34] and biological and environmental samples [20,35]. Microwave digestion procedures are classified according to their operational modes; open vessel microwave assisted digestion, which is more prone to sample contamination, and susceptible to losses of volatile metals and closed (pressurised) vessel procedures, which are rapid and efficient digestion techniques.…”

Measurements of Rare Earth Element and Other Element Mass Fractions in Environmental Reference Materials (NIST SRM 1646a, NIST SRM 1400, IAEA‐395 and IAEA‐450) by INAA, ICP‐AES and ICP‐MS

“…In general, sample heterogeneity becomes serious when a smaller size is used. In the case of NIST SRM 1646a, the recommended minimum test portion size is 500 mg (May and Rumble 2004), but literature values were obtained using 50-250 mg (Crittin et al 2000, Wasserman et al 2001, Dias et al 2002, Lo and Sakamoto 2005, Brahmaji Rao et al 2012, Eriksson et al 2013. To expand the use of the four CRMs used in this study, their sample homogeneity was investigated.…”