摘要:

Urinary α-Ketoglutaric acid was determined by gas chromatography as its trimethylsilylated quinoxalone derivative. Urine was evaporated and the residue reacted with o-phenylenediamine. Ethyl acetate was used to extract the quinoxalone thus formed. The quinoxalone was trimethysilylated and measured with an OV - 17 column. Normal and phenylketonuric urines were analyzed.

ISSN:0003-2719    

DOI:10.1080/00032717208066081

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Quantitative gas chromatography of small amounts of δ1- tetrahydrocannabinol has been demonstrated on a variety of silicone columns. Retention data in the form of methylene unit values were obtained on these columns.

ISSN:0003-2719    

DOI:10.1080/00032717208066082

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A rapid sensitive GLC method for measuring urinary methylmalonic acid (MMA) employing boron trifluoride methylation of the acid is described. The method is sensitive to 1 mg MMA/L and affords MMA recoveries of 96-77 % over a concentration range of 5-2,000 mg MMA/L of urine. Mean daily MMA excretion in 10 normal subjects was 1.33 mg with a range of .56 to 3.2 mg. The daily excretion range of MMA in 5 vitamin B12subjects was 12.5-90 mg/day. These values compare with previously published levels determined using equally sensitive procedures.

ISSN:0003-2719    

DOI:10.1080/00032717208066083

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Sterically hindered 17α-hydroxyl groups in steroids are silylated by trimethylsilylimidazole (TSIM) at 100° C. Decreasing rates of reaction were found for the following structures: 17α, 20β, 21-triol > 17α, 20α-diol > 17α, 20α, 21-triol. When methoxime derivatives are formed as the first step, HCL present in the excess of reagent catalyses the silylation reaction of hydroxyl groups. A simple procedure is described whereby methoxime (MO) derivatives are formed in 15 minutes at 60° C (the 11-one group does not react under these conditions) and persilylated compounds are then prepared in 2 hours at 100° C by reaction with trimethylsilylimidazole.

ISSN:0003-2719    

DOI:10.1080/00032717208066084

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Using thin layers of silica gel and a new pair of solvent systems, thirty-one tryptophan metabolites and related compounds have been separated unambiguously on a single glass plate by two-dimensional chromatography. The chromatographic properties of a further seven compounds in the new solvent system are reported.

ISSN:0003-2719    

DOI:10.1080/00032717208066085

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Trace amounts of selenium are determined coulometrically in urine using electrogenerated iodine.

ISSN:0003-2719    

DOI:10.1080/00032717208066086

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The chemical ionization mass spectra of a group of commonly occuring steroids are discussed. Intense signals (base peak) are observed in the molecular ion region for hydrocarbons and ketones. Functional group elimination is observed with sterols and especially their methyl and TMSi ethers, with the result that base peaks for these compounds are found at m/e values well below the expected molecular ion region. These observations are compared with those from the corresponding electron impact spectra.

ISSN:0003-2719    

DOI:10.1080/00032717208066087

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A continuous scanning photomultiplier which is extremely useful for chemiluminescence reaction studies is described. The scanner is compact, lightweight, very inexpensive, and can be assembled readily without any elaborate shop facilities using hardware accessible in any ordinary laboratory.

ISSN:0003-2719    

DOI:10.1080/00032717208066088

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032717208066080

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor