Acid digestion of geological and environmental samples using open-vessel focused microwave digestion

Taylor, Vivien F.; Toms, Andrew; Longerich, Henry P.

doi:10.1007/s00216-001-1172-z

Cited by 39 publications

(25 citation statements)

References 10 publications

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“…Several minerals and refractory materials are resistant to decomposition by heat, pressure or chemical attack (Allaby 2013). Particularly challenging are coarse-grained granitic rocks, especially those containing significant quantities of large zircon grains that contain low mass fractions of U (Taylor et al 2002). Successful digestion of garnet, sphene, spinel, zircon, rutile and chromite has been performed with acid attack in sealed polytetrafluoroethylene (PTFE) bombs heated at high temperatures (> 160°C) for several days (Yu et al 2001, R evillon andHureau-Mazaudier 2009).…”

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confidence: 99%

Method Development and Optimisation of Sodium Peroxide Sintering for Geological Samples

Bokhari

Meisel

2016

Geostandard Geoanalytic Res

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This work provides a measurement procedure for the complete digestion of rock samples containing refractory minerals such as zircon and chromite. Their dissolution by wet acid digestion is often incomplete but, although providing complete digestions, alkali fusion techniques can result in solutions with a high blank and total dissolved solid content. It was established by the systematic study with reference material trachyandesite MTA‐1 that a 1:6 sample to sodium peroxide (Na2O2) ratio is conservative for the complete digestion and recovery of all the analytes especially those contained in zircon. The sample decomposition time was 120 min for the zircon‐bearing rhyolite reference material MRH‐1. Complete digestion of chromite was obtained in the harzburgite RM MUH‐1. The sample solutions were stable for at least 1 year. Accurate measurements of SiO2, Al2O3, TiO2, P2O5 and K2O could be made with ICP‐MS by not discarding the supernatant of the sinter solution and by using geological reference materials for external calibration. HF digestions are slow, not universal, and may form new mineral/phases that are insoluble under high temperature conditions. The validated sample decomposition procedure combined with ICP‐MS presents an alternative to the use of HF in routine analysis of difficult to digest geological materials.

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confidence: 99%

Method Development and Optimisation of Sodium Peroxide Sintering for Geological Samples

Bokhari

Meisel

2016

Geostandard Geoanalytic Res

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“…However, with rocks and minerals, it frequently leaves undissolved residues because of the relatively short digestion times (within 1 hr) and thus is also not widely used in the digestion of geological materials (Totland et al. 1992, Taylor et al. 2002, Potts and Robinson 2003, Navarro et al.…”

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confidence: 99%

“…Sample decomposition is thus a fundamental and critical stage in the process of geochemical sample analysis (Chao andSanzolone 1992, Yu et al 2001). Many digestion methods have been developed for the decomposition of geological materials such as alkali fusion, open and closed vessel acid digestions and microwave dissolution (Potts 1987, Chao and Sanzolone 1992, Totland et al 1992, Yu et al 2001, Taylor et al 2002, Potts and Robinson 2003. Despite the variety of techniques, complete dissolution of all sample types is still a problem.…”

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confidence: 99%

Reassessment of HF/HNO3 Decomposition Capability in the High-Pressure Digestion of Felsic Rocks for Multi-Element Determination by ICP-MS

Zhang

Liu

et al. 2012

Geostandards and Geoanalytical Research

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Complete dissolution is essential to obtain accurate analytical results for geological samples. Felsic rocks are known to be very difficult to dissolve because of the presence of refractory minerals such as zircon. In this study, we undertook a systematic evaluation of the effect of the HF/HNO3 ratio, digestion time, digestion temperature, digested test portion mass and the presence of insoluble fluorides on analytical results for the felsic rock GSP‐2 using high‐pressure HF and HF/HNO3 digestion. Digestion in mixtures of HF and HNO3 acids is a commonly used method of dissolution for geological samples. However, our results clearly indicate that adding HNO3 inhibited the digestion capabilities of HF for refractory minerals such as zircon. It took 8–12 hr for Zr to be completely recovered in GSP‐2 at 190 °C, whereas it needed about 36 and 72 hr at 160 and 140 °C, respectively. White precipitates were observed in the final solution for test portion mass > 100 mg, irrespective of which of the five different digestion solutions was used (1 ml HF, 2 ml HF, 1 ml HF + 0.5 ml HNO3, 1 ml HF + 1 ml HNO3 and 1.5 ml HF + 1.5 ml HNO3). Environmental scanning electron microscopy showed that these precipitates were mainly composed of AlF3. Instead of further HCl, HNO3 or HClO4 attack, we propose that using ultra‐fine samples and a small sample size is a good way to avoid the formation of insoluble residues (e.g., fluorides). To further investigate the precision and accuracy of the proposed method (using HF alone as the digestion solution during the first acid attack step), a suite of silicate rock reference materials was analysed. Most of the results were found to be in reasonable agreement with the reference values, with a relative error of < 10%.

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“…The concentrations of Al and Ti were approximately three times higher in the HF digest, as expected, however the Si was no longer detectable in the HF digest solution. An HF digest cannot be used to quantify Si because during the digestion, the Si and F will form a volatile complex SiF 4 (10–12). The boiling point of this compound is −86°C, hence the Si is lost from the digestion solution prior to quantification (13).…”

Section: Resultsmentioning

confidence: 99%

Characterization of Undigested Particulate Material Following Microwave Digestion of Recycled Document Papers

McGaw

Szymanski

Smith

2009

Journal of Forensic Sciences

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Recycled document paper was microwave digested in a solution of HNO(3) and H(2)O(2) prior to analysis by inductively coupled plasma mass spectrometry (ICP-MS) to determine the trace elemental concentrations within the paper. Undigested particulate material was observed and subsequently characterized as a mixture of kaolin (clay) and TiO(2) by Fourier transform infrared spectroscopy and X-ray diffraction spectroscopy. The effect of the particulate material on the elemental concentrations was then investigated. Paper samples were completely digested in hydrofluoric acid (HF) and element concentrations determined in the HF and HNO(3)/H(2)O digests were statistically compared using Student's t-test (95% confidence limit). Statistical differences in element concentrations between the two digests were observed for only four elements and there was no evidence of element adsorption by the particulate material. Hence, the HNO(3)/H(2)O(2) digestion proved sufficient to digest paper for ICP-MS analysis, eliminating the need to use the hazardous and corrosive HF matrix.

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Acid digestion of geological and environmental samples using open-vessel focused microwave digestion

Cited by 39 publications

References 10 publications

Method Development and Optimisation of Sodium Peroxide Sintering for Geological Samples

Method Development and Optimisation of Sodium Peroxide Sintering for Geological Samples

Reassessment of HF/HNO3 Decomposition Capability in the High-Pressure Digestion of Felsic Rocks for Multi-Element Determination by ICP-MS

Characterization of Undigested Particulate Material Following Microwave Digestion of Recycled Document Papers

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