摘要:

The measurement of selenium concentrations in marine organisms is described. After decomposition of samples with nitric, perchloric and sulphuric acids, selenium was isolated by coprecipitation with lanthanum hydroxide. Selenium was subsequently reduced to hydrogen selenide by sodium tetrahydroborate solution, trapped in a potassium iodide-iodine solution and determined by electrothermal atomic absorption spectroscopy. The minimum selenium concentration detectable using this method is 0.01 μg/g starting with l g of sample. At the 0.8 μg/g level selenium was determined with a coefficient of variation of 6%. Typical results obtained for macroalgae, fish and molluscs are given.

ISSN:0003-2719    

DOI:10.1080/00032718308065217

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A rapid and simple spectrophotometric method was developed for the determination of nitrite in wastewater. The procedure was based on the extraction of nitrite with ethyl acetate solution of 4,5-dihydroxycoumarin. Beer's law obeyed up to 0.75 ppm of nitrite-nitrogen. Results obtained by using the proposed method on waste-water samples agreed well with those obtained by the diazotising-coupling method.

ISSN:0003-2719    

DOI:10.1080/00032718308065218

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A rapid field-test of ascorbic acid content in fruit juices is feasible by the application of indicator papers capable for approximate quantitation.

ISSN:0003-2719    

DOI:10.1080/00032718308065219

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A sensitive and selective method has been developed for the spectrophotometric determination of antimony in the tervalent oxidation state. It was found that antimony (III) reacts with mandelic acid to form a complex anion extractable into chlorobenzene with malachite green in weak acidic media (pH 2.2 to 3.5) at room temperature and is determined indirectly by measuring the absorbance of malachite green in the extract at 628 nm. The calibration graph is linear for antimony (III) over the range 0.088–1.8 mg 1−1(7.2 × 10−7–1.5 × 10−5mol 1−1) with the apparent molar absorptivity ϵ × 6.9 × 1041 mol−1cm−1. Antimony (V) was slightly extracted in the presence of phosphate buffer with ϵ × 2.7 × 1031 mol−1cm−1.

ISSN:0003-2719    

DOI:10.1080/00032718308065220

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Fundamental operational parameters like temperature, weight of samples, and time of drying, charring, and atomization are optimized for direct determination of calcium, magnesium, and iron in siliceous materials (feldspar and lime). The use of low intensity absorption lines together with the dispersion of the samples in a graphite matrix, allows the technique to be applied to materials containing up to 2.1% CaO, 0.36% MgO, and 0.75% Fe2O3. The results are compared with those obtained by flame and graphite furnace atomic absorption spectrometry using standard solutions. The correlation found between the three techniques and the reported composition of NBS samples are highly satisfactory.

ISSN:0003-2719    

DOI:10.1080/00032718308065221

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Fluoride ion was determined by means of a fluoride ion selective electrode on geothermal-geopressured brines obtained from the DOW-DOE L. R. Sweezy#1 Well. The values decrease from 7.8ppm to a plateau value of 1.6–1.8 ppm.

ISSN:0003-2719    

DOI:10.1080/00032718308065222

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The performance of a polarographic analyser equipped with a long-lasting, sessile-drop mercury electrode is described in the direct, simultaneous determination of heavy metals (cadmium, copper and lead) in some Coca Cola samples (drawn from commercial bottles or tins). The determinations were performed by the differential pulse anodic stripping voltammetric technique using a programmed fully automated sequence (i.e., deposition-stripping-recording). The results obtained (1-3, 6-25 and 1.5-3.3 ppb for cadmium, copper and lead, respectively) as well as those previously obtained in the stripping analysis of some sea-waters and mineral-waters samples suggest that the proposed automated device ensures sufficient sensitivity and accuracy to be employed in the DPASV determination of toxic metals (at trace and subtrace levels) in natural waters and beverages.

ISSN:0003-2719    

DOI:10.1080/00032718308065223

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0003-2719    

DOI:10.1080/00032718308065216

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor