Microwave oven-based wet digestion technique

Barrett, P. F.; Davidowski, Leon J.; Penaro, Kenneth W.; Copeland, Thomas R.

doi:10.1021/ac50029a054

Cited by 68 publications

(16 citation statements)

References 9 publications

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“…Urine samples were diluted in Triton X-100 (0.5% Triton X-100, 0.125% Antifoam Emulsion B, and 0.35% HN03). Prior to analysis by AAS, fecal samples were digested with HN03 according to a microwave digestion technique as described in the literature (20)(21)(22). Under these conditions quantitative recovery of selenium from feces or urine spiked with selenite, BSC, or DBS was found.…”

Section: Methodsmentioning

confidence: 99%

Metabolism of [14C]benzyl selenocyanate in the F344 rat

El‐Bayoumy

Upadhyaya

Date

et al. 1991

Chem. Res. Toxicol.

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Benzyl selenocyanate (BSC), a synthetic organoselenium compound, has been shown to inhibit chemically induced tumors in several animal model systems. However, it is not known whether BSC or one of its metabolites is responsible for the chemopreventive effect. An initial approach to this question requires the structural elucidation of BSC metabolites in vitro and in vivo. To determine the structures of BSC metabolites in vitro, we studied the metabolism of [14C]BSC using Aroclor-induced rat liver 9000g supernatant. Under these conditions, BSC was partially converted to dibenzyl diselenide (DDS) and phenylmethaneseleninic acid. The metabolism of [14C]BSC (12.5 mg/kg body weight, 8 mCi/mmol, oral administration) in male F344 rats was also studied. Excretion was monitored by measurement of radioactivity as well as by selenium content using atomic absorption spectrophotometry (AAS). The results indicate that urine was the major route of excretion. Approximately 22% of the dose was excreted in the urine over the course of 35 days; however, a large portion (approximately 70%) of the dose remained in the body. Benzoic acid, hippuric acid, and their sulfate and glucuronide conjugates, accounting for 16% of the dose, were identified in the urine. The formation of these metabolites indicates that BSC is metabolized in part via bond cleavage between the benzyl moiety and the selenocyanate function. Additional support for this cleavage was obtained from fecal analysis; over the course of 23 days 9% of the selenium (AAS) but only less than 1% of the radioactivity was recovered in feces. No radioactivity was detected in the exhaled air. We also studied the metabolism of [14C]DDS (17.3 mg/kg body weight, 2.5 mCi/mmol) in male F344 rats.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Methodsmentioning

confidence: 99%

Metabolism of [14C]benzyl selenocyanate in the F344 rat

El‐Bayoumy

Upadhyaya

Date

et al. 1991

Chem. Res. Toxicol.

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“…The very first application of 2.45 GHz microwaves in processing began with heating and cooking food in kitchens all over the world. However, the use of microwaves in analytical laboratories began later, starting with drying organic and inorganic samples in order to determine the amount of moisture [1] and later it was used for the dissolution or decomposition of not only biological but also geological materials [2][3][4][5].Komarneni and Roy pioneered the use of microwaves in the liquid state for synthesis and published a seminal paper in Materials Letters in 1985 [6,7]. Unfortunately, the historical significance of this paper entitled "Titania gel spheres by a new sol-gel process" was not recognized by many as the title of this paper did not itself refer to microwaves.…”

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confidence: 99%

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confidence: 99%

Inorganic Syntheses Assisted by Microwave Heating

Leonelli

Komarneni

2015

Inorganics

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This Special Issue on "Inorganic Syntheses Assisted by Microwave Heating" represents one of the few fully dedicated issues on inorganic microwave synthesis published by any international scientific journal and it features five papers and one review article.Microwave irradiation has been used for many years to accelerate chemical reactions. The very first application of 2.45 GHz microwaves in processing began with heating and cooking food in kitchens all over the world. However, the use of microwaves in analytical laboratories began later, starting with drying organic and inorganic samples in order to determine the amount of moisture [1] and later it was used for the dissolution or decomposition of not only biological but also geological materials [2][3][4][5].Komarneni and Roy pioneered the use of microwaves in the liquid state for synthesis and published a seminal paper in Materials Letters in 1985 [6,7]. Unfortunately, the historical significance of this paper entitled "Titania gel spheres by a new sol-gel process" was not recognized by many as the title of this paper did not itself refer to microwaves. Nevertheless, the abstract clearly states that microwaves led to fast reaction as follows and we quote: "A new technique is devised for the preparation of solution derived titania gel spheres. The gel sphere preparation process involves the dispersal of the polymerized titanium ethoxide solution into a two-phase liquid suspension in kerosene followed by heating in a microwave oven. This is a simple and fast method for the preparation of xerogel spheres with diameter in the range of tens of micrometers which may be useful in coating technology by plasma-spraying". Gedye et al., 1986 [8] and Gigure et al., 1986 [9] may have been the first to report on the use of microwaves for organic syntheses in 1986. These two papers are generally recognized as pioneering OPEN ACCESS

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“…Although we are pleased that the EPA has accepted a closed vessel microwave digestion for the Contract Laboratory Program (CLP), we must caution users with regard to this specific digestion procedure when attempting to extract Sb from potentially contaminated geological materials. Microwave heated acid dissolutions offer numerous advantages over conventional hot-plate digestions (2)(3)(4)(5)(6)(7), but the use of only HN03 for the dissolution of Sb from soils results in losses of this metal. For two geological materials, a standard soil from the Rocky Mountain Arsenal (RMA), and a National Institute of Standards and Technology (NIST) standard reference river sediment (SRM-2704), we found that a microwave-HN03 digestion similar to the one in the EPA's Statement of Work failed to recover Sb for GFAA analysis (7).…”

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confidence: 99%