Resolution of racemic aspartic acid, tryptophan, hydroxy and sulfhydryl amino acids by gas chromatography

Pollock, Glenn E.; Kawauchi, Akihiko

doi:10.1021/ac60264a059

Cited by 39 publications

(8 citation statements)

References 16 publications

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“…Only by sacrificing resolution of D-leucine from proline can this interference (with the NTFA derivatives) be avoided. The alternative that we have employed is to destroy the TFA serine derivative by addition of methanol to the completed derivative followed by refrigerated overnight storage (Pollock and Kawauchi, 1968). By following this procedure, good agreement between isopropyl and butanol has been observed ( Table 2, data for laboratory E).…”

Section: Resultsmentioning

confidence: 99%

Interlaboratory Comparison of Amino Acid Enantiomeric Ratios in Fossil Pleistocene Mollusks

Wehmiller

1984

Quat. res.

116

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Enantiomeric (d/l) ratios of eight amino acids in three homogeneous powdered fossil Pleistocene mollusk samples have been compared. Eleven laboratories have contributed results to this effort. Three gas chromatographic methods and one ion-exchange chromatographic method were used. In general, the coefficients of variation (c.v.) are best for alanine, glutamic acid, and aspartic acid (3–8%). For leucine and phenylalanine, the c.v.'s are between 5 and 10%. For isoleucine, proline, and valine the c.v.'s range from 10 to 18%. Individual laboratories usually report analytical precision of between 2 and 5%, but it is clear that significant differences between laboratories' results are often encountered, and that these analytical differences could, in some cases, lead to very significant differences (25% or more) in age estimates based upon enantiomeric ratios. Multiple analyses of desalted hydrolyzates of these powder samples suggest that interlaboratory differences are often caused by instrumental and/or derivatization procedures rather than the wet-chemical sample preparative steps. It is proposed that the powder samples described here be used in all future publications of fossil amino acid enantiomeric ratio data.

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Section: Resultsmentioning

confidence: 99%

Interlaboratory Comparison of Amino Acid Enantiomeric Ratios in Fossil Pleistocene Mollusks

Wehmiller

1984

Quat. res.

116

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“…Like phosphatidylethanolamine, phosphatidylserine forms a dinitrobenzamide which possesses excellent solvent partition properties especially following further methylation (4), but this derivative is difficult to recover from the reaction mixture when present in small amounts. Much more readily prepared and re-Ipresented in part at the JOCS-AOCS Joint Meeting, Los Angeles, 1972. covered are the trifluoroacetamides of phosphatidylserine in which the polar amino group is masked resulting in greatly improved chromatographic properties, as already demonstrated for amino alcohols (5) and amino acids (6,7). As a background for studies of the metabolism of molecular species, the present report describes the preparation of trifluoroacetamides from synthetic and natural phosphatidylserines and phosphatidylethanolamines along with their separation into different classes of unsaturation by AgNO3-TLC.…”

Section: Introductionmentioning

confidence: 83%

Resolution of molecular species of intact serine and ethanolamine phosphatides by argentation chromatography of their trifluoroacetamides

Yeung

Kuksis

Marai

et al. 1977

Lipids

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An effective resolution of intact phosphatidylserines on the basis of unsaturation has been achieved by conventional argentation thin layer chromatography (TLC) following trifluoracetylaction. The trifluoroacetamides are prepared by treatment with trifluoroacetic anhydride or N-methyl-bis-trifluoroacetamide. The acetamides are resolved with chloroform-methanol-water (65:25:4, v/v/v) on Silica Gel G containing 20% silver nitrate. Subfractions with 0-6 double bonds per molecule were obtained for the phosphatidylserines of pig and ox brain, pig erythrocytes, rat liver, and rabbit skeletal muscle. The preparation of trifluoroacetamides is also advantageous for the silver ion fractionation of phosphatidylethanolamines. The method is applicable to metabolic studies of molecular species using radioactive precursors of neutral lipids, phosphorus, and nitrogenous bases.

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“…After standing 30 min, the O-PFP group was removed, and the sample was evaporated in an ice bath to remove the methanol and methylene chloride. This pyridine-methanol accelerated removal of the O-PFP group was used in preference to that described in (14) because the O-PFP group does not transesterify very rapidly with methanol alone as does O-TFA groups. The O-acetylation of the free hydroxyl, N-PFP amino acid ester can, however, be accomplished using the procedure described in ( 14), and the final derivative diluted with methylene chloride for analysis.…”

Section: Methodsmentioning

confidence: 99%

“…With this background, and the fact that geochemists have proposed in recent years that the rate of racemization of amino acids might be used as a method for age dating or geothermometry (10)(11)(12), we decided to reinvestigate the content of D-amino acids in soils by using a gas chromatographic technique which would enable us to determine more specifically the identity of these isomers (13)(14)(15). This method involves esterification of the amino acids with (+)-2-butanol, followed by acylation of the remaining functional groups with trifluoroacetic anhydride (TFA) or other perfluoroalkanoyl anhy-tiride.…”

mentioning

confidence: 99%

Determination of the D and L isomers of some protein amino acids present in soils

Pollock¹,

Cheng²,

Cronin³

1977

Anal. Chem.

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The o and l isomers of some protein amino acids present In soils were measured by using a gas chromatographic technique. The results of two processing procedures were compared to determine the better method. Results of the comparison indicated that the determination of o and l percentages requires amino acid purification If one is tb obtain accurate data. It was found that very significant amounts of o-alartlne, o-aspartic acid, and o-glutamic acid were present in the contemporary soils studied. Valine, isoleucine, leucine, proline, and phenylalanine generally contained only, a trace to very Small amounts of the o isomer. It is probable that the o-amlno acids from the alanine, aspartic, and glutamic acids are contributed to the soil primarily via microorganisms. The flridlng of very significant quantities of some D-amino acids (~S-16%)In present-day soils may alert some Investigators of geological sediments to a possible problem In using amino acid racemization as an age-dating technique.

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Resolution of racemic aspartic acid, tryptophan, hydroxy and sulfhydryl amino acids by gas chromatography

Cited by 39 publications

References 16 publications

Interlaboratory Comparison of Amino Acid Enantiomeric Ratios in Fossil Pleistocene Mollusks

Interlaboratory Comparison of Amino Acid Enantiomeric Ratios in Fossil Pleistocene Mollusks

Resolution of molecular species of intact serine and ethanolamine phosphatides by argentation chromatography of their trifluoroacetamides

Determination of the D and L isomers of some protein amino acids present in soils

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