Gas Chromatography Of Amino Acids Research Articles

Hydroxyproline interference during the gas chromatographic analysis of D/L aspartic acid in human dentine.

The proportion of D- to L-enantiomers of aspartic acid in metabolically isolated proteins has been used by forensic scientists to estimate age at death. We have demonstrated the interference of a derivative of hydroxyproline (N-TFA isopropyl Hyp ester) with the N-TFA isopropyl L-Aspartic (Asp) acid ester during gas chromatography of amino acids. This has serious implications for the accurate quantification of the D- to L-Asp ratio extracted from collagenous proteins. Having demonstrated the potential for this co-elution in amino acid standards, acid-soluble dentine proteins and non-mineralised collagen, we argue that this problem can be overcome either by high resolution separation or by analysis of the (Hyp-poor) non-collagenous protein fraction.

Standardization of cation-exchange clean-up prior to gas chromatography of amino acids

The optimum conditions for the cation-exchange clean-up of amino acids, present in protein hydrolysates, prior to their gas chromatographic determination were investigated. The results of exchaustive study monitoring the amounts of amino acids as N,O(S)-trifluoroacetyl isobutyl esters, revealed that the recovery of amino acids from the column was affected appreciably by either the particle size or the divinylbenzene content of the resins. Quantitative recovery and reproducible determination of amino acids require (i) a 50-fold excess of resin (calculated as equivalent capacity relative to the amino acids present) and (ii) sufficient amounts of eluates: the volumes both of distilled water and of 7 M ammonia solution must be about six times the volume of the wet resin applied. Under optimum conditions the recoveries of alanine, glycine, threonine, serine, valine, leucine (isoleucine), proline, hydroxyproline, methionine, aspartic acid, phenylalanine, ornithine, glutamic acid, tyrosine, lysine, arginine and cystine, were quantitative, both without and after hydrolysis, and that of tryptophan was ca. 85%.

Capillary gas chromatography of amino acids as their tert‐butyldimethylsilyl derivatives in the analysis of serum amino acids in metabolic diseases

AbstractReaction of amino acids with N‐methyl‐N‐(tert‐butyldimethylsilyl)trifluoroaceamide (MTbSTFA) in acetonitrile affords good yields of amino acid derivatives with excellent gas chromatographic and mass spectrometric properties. The single‐step derivatization procedure is highly reproducible. The TBDMS amino acids are stable at room temperature for at least three days. Only a single peak is observed for each amino acid. The procedure allows simultaneous analysis of asparagine and glutamine together with other serum amino acids. Separation is achieved on a borosilicate glass capillary coated with OV‐1. The mass spectra of the TBDMS amino acids possess characteristic diagnostic ions. These properties were used in the sensitive detection by GC‐MS and SIM‐GC‐MS of GABA and pipecolic acid in the serum of a newborn suspected of a Zellweger‐type syndrome, which could not be detected by other methods.

Capillary gas chromatographic analysis of amino acids in blood and protein hydrolysates as tert.-butyldimethylsilyl derivatives

A method is given for a one-step derivatization and gas chromatography of amino acids in blood and protein hydrolysates. Blood samples are partially purified by solvent extraction. Protein hydrolysates are neutralized with a triethylamine solution. Then tert.-butyldimethylsilyl derivatives of the amino acids are prepared in a one-step procedure and separated on a 30-m fused-silica SE-30 capillary column. Except for tryptophan and cystine, amino acids are eluted within 30 min. Amino acids are derivatized more rapidly than their corresponding trimethylsilyl derivatives and do not degrade on the long fused-silica columns.

Capillary gas chromatography of amino acids, including asparagine and glutamine: sensitive gas chromatogaphic—mass spectrometric and selected ion monitoring gas chromatographic—mass spectrometric detection of the N,O(S)- tert.-butyldimethylsilyl derivatives

Amino acids and the amino amides glutamine and asparagine can be simulataneously derivatized to the corresponding N,O(S)- tert.-butyldimethylsilyl derivatives in a one-step reaction with N-methyl-N-( tert.-butyldimethylsilyl)trifluoroacetamide in acetonitrile. The solution is used directly for gas chromatography (GC). Losses due to evaporation steps are avoided. Except for the more basic amino acids, derivatization occurs at room temperature. Lysine, arginine and histidine require additional heating at 150δC for 2.5 h in order to complete derivatization. The derivatization has high reproducibility. The response factors relative to norvaline or cycloleucine lie between 0.40 and 1.30. Arginine is the most difficult amino acid to derivatize. The sizwe of the tert.-butyldimethylsilyl (TBDMS) groups prevents multiple silylation of the nitrogen atoms. Only a single peak is observed for each compound Twenty-seven amino acid (and glutamine and asparagine) derivatives were simultaneously chromatographed and well separated in a single run on a 25 m × 0.20 mm I.D. glass capillary column coated with OV-1. The TBDMS derivatives possess very characteristics. EI mass spectra at 70 eV, with intense diagnostic ions. This makes them very appropriate for GC—mass spectrometric (MS) work and selected ion monitoring GC—MS at the picomole level. The detection limit for arginine as the TBDMS derivative is less than 0.3 ng. The usefulness of the method is illustrated by the detection of amino acids in a peptide hydrolysate obtained from 1 μg of bovin insulin B-chain.

Gas chromatography of amino acids: Use of a fused‐silica capillary column in the determination of plasma amino acids

AbstractA capillary chromatographic procedure using a fused silica column is described which can be used to quantitatively determine amino acids in plasma following the pre‐chromatographic “clean‐up” described in a recent paper [1]. In substituting this procedure for that involving a packed column, advantage has been taken of the greater resolving power to separate amino acids from background component peaks. In order to extend this advantage and provide a sound basis for quantitative analysis, the technique of cold on‐column injection was employed. As a result, good precision of standard analysis was obtained with relative standard deviation (RSD) values for all amino acids of less than 4%. Application of the entire procedure to plasma samples yields RSD values of better than 10% for all amino acids with recoveries ranging from 72% to 104%. Simultaneous determination of plasma amino acid levels by gas chromatography (GC) using capillary columns and by classical ion exchange (CIE) showed reasonable agreement. Statistical evaluation showed no significant difference between twelve amino acids. Values for the remaining two, namely, phenylalanine and histidine are significantly different (p < 0.005). Comparison of the values obtained from GC capillary and packed columns reveals no significant difference between fourteen amino acids. Significant differences exist between results for phenylalanine and tyrosine (p < 0.001). It is concluded that there is good agreement between data obtained by GC capillary and CIE techniques and that differences between results for phenylalanine and histidine are method related.

Gas chromatography of amino acids in urine: identification and removal of creatinine as the major interfering substance

Gas chromatography of amino acids in urine: identification and removal of creatinine as the major interfering substance

Gas chromatography of amino acids in urine and haemofiltrate

Capillary gas chromatography of amino acid derivatives obtained from biological material shows a large number of previously unknown constituents. The profiles of amino acids obtained from urine of healthy individuals and haemofiltrate of uraemic patients indicate that haemofiltration removes some amino acids to a considerably higher extent from uraemic patients than the kidney does from healthy persons. For instance, if haemofiltration is required three times a week, an approximately ten-fold amount of the essential amino acid methionine and a forty-fold amount of the essential amino acid leucine is lost compared to their excretion in urine by a healthy individual over the same period.

Gas chromatography of amino acids

This review summarizes all papers that have appeared on the gas chromatography of amino acids (including the iodoamino acids) and their enantiomers in the period 1956-mid-1974. It has been found that the methods used for analysis of amino acids can be divided into three classes: (1) degradative procedures and techniques for converting the amino acid into another chemical compound; (2) procedures based on esterification of the carboxyl group and derivatization of the α-amino and other reactive groups in at least two steps; and (3) procedures based on a simultaneous derivatization of the carboxyl and α-amino groups in one reaction medium. For the treatment of the amino acid or its alkyl ester, three approaches can be distinguished for the two latter cases, i.e., acylation, alkylation (including silylation) and condensation. Of the procedures used for the resolution of optical antipodes, two methods are discussed, namely analysis of diastereoisomers on optically inactive stationary phases and separation of enantiomers on optically active stationary phases.

Gas chromatography of amino acids as n-thiocarbonyl ester derivatives

Gas chromatography of amino acids as n-thiocarbonyl ester derivatives

Quantitative gas chromatography of amino acids: Interesterification studies

The reaction conditions for quantitative interesterification of amino acids from methyl to n-butyl esters have been determined. Temperature was more significant than the concentration of interesterification catalyst. Complete conversion to n-butyl esters was achieved by increasing the reaction temperature from 90° to 100°C. Also, the time required for interesterification was reduced by 30 min. This improved procedure represents an advance in the development of a quantitative method of analysis of amino acid by gas-liquid chromatography.

Pyrolysis Gas Chromatography of Amino Acids and Proteins

タンパク質の構成アミノ酸を迅速,簡易に推定するため,アミノ酸,タンパク質の熱分解ガスクロマトグラフィーを行なった。分離管としてhexanedione,tetraetllyleneglyco ldimethylether,dioctylphthalateの3種の管を連結したものと,Silicone D.C.550の両者を使用した。アミノ酸18種の熱分解ガスクロマトグラム・パターンのピークの面積比が種類によって異なることからタンパク質の熱分解パターンと比較することを考えた。タンパク質試料としてミルクカゼイン,卵白アルブミンを用い,ピークの面積比と種類から構成アミノ酸を推定した。つぎに結果を確かめるためタンパク質試料をアミノ酸分析装置で分析して比較したところ特異性の乏しいパターンを与える二,三のアミノ酸を除いては存在の有無がほぼ推定できた。

Quantitative gas chromatography of amino acids

Received March 5, 1965 Because of its speed, accuracy, and sensitivity, gas chromatography offers advantages over other chromatographic methods for the determination of amino acids. Among derivatives which have been investigated are the trimethylsilyl Ntrimethylsilyl esters (h Hagen and Black, 1964; Cruickshank and Sheehan, 1964). Each of these derivatives has proved to be useful for gas-chromatographic separations, but none has been studied in sufficient detail to permit general analytical use. It was recognized that quantitative, reproducible derivative formation was an essential prerequisite for an accurate gas-chromatographic method, thus studies were made to investigate the organic reaction conditions necessary for quantitatively converting amino acids to volatile derivatives. This paper describes a general method for quantitative and

QUANTITATIVE GAS CHROMATOGRAPHY OF AMINO ACIDS. PREPARATION OF N-BUTYL N-TRIFLUOROACETYL ESTERS.

QUANTITATIVE GAS CHROMATOGRAPHY OF AMINO ACIDS. PREPARATION OF N-BUTYL N-TRIFLUOROACETYL ESTERS.

GAS CHROMATOGRAPHY OF AMINO ACIDS. 1. ANALYSIS OF THE MIXTURE OF METHYL-NTRIFLUOROACETYL DERIVATIVES.

Journal Article Gas Chromatography of Amino Acids: I. Analysis of the Mixture of Methyl-N-trifluoroacetyl Derivatives Get access NOBUO IKEKAWA NOBUO IKEKAWA Institute of Physical and Chemical ResearchKomagome, Bunkjo-ku, Tokyo Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Biochemistry, Volume 54, Issue 3, September 1963, Pages 279–282, https://doi.org/10.1093/oxfordjournals.jbchem.a127784 Published: 01 September 1963 Article history Received: 20 April 1963 Published: 01 September 1963