摘要:

Until now there has been no attempt to write the complete history of analytical chemistry in Romania. Nevertheless, we consider it important that our young chemists learn about the history of analytical chemistry in our country, because you can never step forward if you disregard the past. Furthermore, scientists in other countries might find the history and current status of analytical chemistry in Romania of interest.

ISSN:0003-2719    

DOI:10.1080/00032717208064334

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The speed of trimethylsilylation of sterically hindered phenols was increased by promoting the reaction with a small amount of trifluoroacetic acid. Promotion was successful with hexamethyldisilazane, trimethylchlorosilane, bis-(trimethylsilyl)-trifluoroacetamide, bis-(trimethylsilyl)-acetamide, and trimethylsilylimidazole.

ISSN:0003-2719    

DOI:10.1080/00032717208064335

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Combining a simple chromatographic system on celite microcolumns with partially specific antisera as binding reagents, simultaneous radioimmunoassay of dehydroepiandrosterone and 16a-hydroxydehydroepiandrosterone could be performed on the same aliquot of plasma. These steroids have been measured in plasma samples obtained from subjects of both sexes under various conditions.

ISSN:0003-2719    

DOI:10.1080/00032717208064336

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Fatty acid methyl esters may be formed by dissolving the fatty acids in a 0.2 M solution of trimethylanilinium hydroxide in methanol and injecting the solution into a gas chromatograph. The reaction is rapid and quantitative, and the reagent appears to be less hazardous than diazomethane.

ISSN:0003-2719    

DOI:10.1080/00032717208064337

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Chloromethyldimethylsilyl (CMDMS) ethers are useful derivatives for combined gas chromatography-mass spectrometry. They have characteristically longer retention times than the corresponding trimethylsilyl (TMS) derivatives, and this permits effective fractionation of mono-, di-, and trihydroxy steroids. CMDMS ethers provide mass spectra comparable with those of TMS ethers, but ions containing the CMDMS group are readily recognisable in the former by virtue of the two abundant natural isotopes of chlorine. This facilitates interpretation of spectra and may be expected to aid the location of drug metabolites by selective ion monitoring.

ISSN:0003-2719    

DOI:10.1080/00032717208064338

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A glass injection system consisting of a packed precolumn and gasphase splitter has been developed for the introduction of derivatized biological samples on glass capillary columns. The precolumn provides complete sample evaporation before the splitter zone, traps contaminating nonvolatiles, and prevents decomposition or adsorption of components. In addition, a carrier gas control system is described that permits stable and repeatable adjustment of split ratio and capillary inlet pressure.

ISSN:0003-2719    

DOI:10.1080/00032717208064339

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A spectrophotometric titration for the determination of rhenium was developed using tin(II) as the titrant. Samples containing approximately 1 × 10−2meq/ml were titrated with errors of approximately four percent. Titration of rhenium was investigated in the presence of glucose, ethanol, and oxalate. No significant induced reactions were shown to occur.

ISSN:0003-2719    

DOI:10.1080/00032717208064340

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The effects of surfactants on fluorescence analysis were studied. The addition of surfactants to a metal complex solution causes a remarkable enhancement of fluorescence. By means of such phenomenon the sensitivity of the fluorometric determination of aluminum was increased about six-fold over conventional methods. From the stability of the chelate complex in the presence of surfactant and the degree of enhancement of fluorescence, the nonionic surfactant was judged to be the most useful of the types of surfactants: cationic, anionic and nonionic. An ultramicro amount of aluminum, 5 × 10−10g Al/ml, could be determined by the proposed method.

ISSN:0003-2719    

DOI:10.1080/00032717208064341

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Polarography with a sodium carbonate-oxalic acid supporting electrolyte was used to determine both Fe(II) and Fe(III) simultaneously in actual coal mine water samples. The average relative percent error was 2.2% for Fe(II) and 2.1% for Fe(III) over a range of 10 to 500 ppm. In actual mine water the Fe(II) content was highest where the mine water emerged. As the water moved down stream from the source of pollution Fe(II) decreased and Fe(III) concentration increased as Fe(II) was oxidized to Fe(III) by oxygen. This was accompanied by a decrease in pH. Further down the stream Fe(III) started to precipitate and then its concentration steadily decreased.

ISSN:0003-2719    

DOI:10.1080/00032717208064342

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A new method for the determination of the amino acid arginine utilizes a dual enzyme catalyzed reaction monitored with an ammonium ion selective membrane electrode of the antibiotic type. The technique gives a linear correlation between arginine concentration and electrode response over the 3 × 10−3Mto 3 × 10−5Mrange and a useful, but non-linear, response over a wider range. Major interferences are urea, K+, and NH4+, but Na+does not interfere in the physiological concentration range.

ISSN:0003-2719    

DOI:10.1080/00032717208064343

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor