Determination Of Glutamic Acid Research Articles

Outside Front Cover: On-line electroextraction in capillary electrophoresis: Application on the determination of glutamic acid in soy sauces

DOI: 10.1002/elps.201800203 An on-line, single step electroextraction is demonstrated for capillary electrophoresis and microchip electrophoresis. The electroextraction employed an aqueous two-phase system (ATPS) formed by one 500 kDa dextran-rich phase added to the samples and a second 6 kDa poly(ethylene glycol)-rich phase containing 5.0 mol/L acetic acid. The second phase acted as background electrolyte. The ATPS enabled electrically driven extraction of target compounds, while demonstrated to retain sodium ions. The ATPS electrodriven system was applied on the determination of glutamate in soy sauces samples.

On-line electroextraction in capillary electrophoresis: Application on the determination of glutamic acid in soy sauces.

We present an on-line, single step coupling between liquid-liquid extraction and capillary electrophoresis with capacitively coupled contactless conductivity detection, which allows an efficient analysis of complex food matrices with high sodium content. The sodium depletion was demonstrated using an aqueous two-phase system. The aqueous two-phase system enables the electrically driven extraction of the target compounds. The sample was prepared in Dextran-rich phase (8% w/v 500 kDa Dextran, DEX). The background electrolyte (acetic acid 5.0 mol/L) contained 6% w/v of 6 kDa PEG. As proof of applicability, we employed the developed method for glutamic acid quantification on soy sauces. The peak area of glutamic acid presents no significant difference (α=0.05), while the peak area of the sodium presented a reduction of 11.7±0.2 and 19±3% for premium and low-cost soy sauce samples analyzed. The glutamic acid concentration for premium soy sauce sample was 2.7±0.8 and 4.8±0.4 g/L, and for low-cost soy sauce sample, the concentration was 9.9±0.9 g/L, which agreed with those obtained by other analytical techniques.

Determination of glutamic acid in biological material by capillary electrophoresis

The conditions for the identification and determination of Glutamic acid by capillary zone electrophoresis without their preliminary derivatization have been optimized. The effect of concentration of buffer electrolyte and pH on determination of Glutamic acid has been investigated. It is shown that the 5 Mm borate buffer concentration and a pH 9.15 are optimal. Quantitative determination of glutamic acid has been carried out using a linear dependence between the concentration of the analyte and the area of the peak. The accuracy and reproducibility of the determination are confirmed by the method "introduced - found". Glutamic acid has been determined in the placenta homogenate. The duration of analysis doesn't exceed 30 minutes. The results showed a decrease in the level of glutamic acid in cases of pregnancy complicated by placental insufficiency compared with the physiological, and this fact allows to consider the level of glutamic acid as a possible marker of complicated pregnancy.

Determination of Glutamic Acid and Aspartic Acid in Tomato Juice by Capillary Isotachophoresis

A capillary isotachophoresis method was developed and applied for determination of glutamic acid and aspartic acid in tomato juice samples. The leading electrolyte was 10 mmol L−1 L-histidine monohydrochloride including 1% poly (vinylpyrrolidone) adjusted with histidine to pH 5.5. The terminating electrolyte was 5 mmol L−1 2-morpholineethanesulfonic acid adjusted to pH 6.0 with tris(hydroxymethyl)aminomethane. It was proved that the developed method is suitable for a routine analysis of glutamic and aspartic acid in tomato juice. The simplicity and low cost of this analytical procedure makes the technique a good alternative to high performance liquid chromatography. Usefulness of the method was tested on different varieties of tomatoes as well as different ripeness stages of the fruits. Moreover, commercial tomato juices were also analysed.

Determination of glutamic acid and gamma-aminobutyric acid in Ringer's solution without desalination at the femtomole level by gas chromatography chemical ionization mass spectrometry.

For the quantification of glutamic acid in Ringer's solution, pentafluoropropionic methyl ester was the most sensitive derivative. The detectable concentration was 0.01 microM glutamic acid in Ringer's solution; the amount of the preparation was 1 pmol and the injection into a gas chromatograph mass spectrometer was 10 fmol. For the quantification of gamma-aminobutyric acid in Ringer's solution, the trifluoroacetal-hexafluoropropionyl ester was quantification of gamma-aminobutyric acid in Ringer's solution, the trifluoroacetal-hexafluoropropionyl ester was detectable at a concentration of 0.01 microM. Ringer's salts facilitated acylation in the order heptafluorobutyric anhydride greater than pentafluoropropionic anhydride greater than trifluoroacetic anhydride. The effect depended on esterification of carboxy groups in the order methyl ester greater than hexafluoropropionyl ester greater than butyl ester. Sodium carbonate, sodium acetate and sodium citrate also facilitated acylation with pentafluoroproionic anhydride, while sodium phosphate inhibited the acylation and sodium sulfate inhibited it slightly. The pentafluoropropionic methyl ester of glutamic acid was stable for up to 10 days, when it was dissolved in acetone and stored at -18 degrees C.

Quantitative gas chromatographic determination of glutamic acid, 2-pyrrolidone-5-carboxylic acid and 2-pyrrolidone

Quantitative gas chromatographic determination of glutamic acid, 2-pyrrolidone-5-carboxylic acid and 2-pyrrolidone

The isolation of poly-alpha-L-glutamic acid from the oviduct of the domestic fowl.

These investigations were carried out with the object of isolating from specific regions of the oviduct of the domestic fowl substances which might be effective in prolonging the survival of avian sperm in vitro . Poly- α -L-glutamic acid has been isolated from the infundibulum, upper magnum and utero-vaginal junction of oviducts from domestic fowls in full lay. The molecular weight was found to be 73 600 by specific viscosity and 81 500 as determined by end group analysis. The structure was proved by quantitative determination of glutamic acid in hydrolysates of the purified material, by establishing the L-configuration of the glutamic acid so produced, by comparison of the infra red spectrum of the product with those of synthetic poly- α -L-glutamate, and with bacterial poly- γ -DL-glutamate, and by the immunological specificity of antiserum prepared in rabbits to the purified natural product. Poly- α -L-glutamic acid was found to preserve the motility of cock sperm for several hours in vitro at the body temperature of the fowl. This effect appears to be specific to Poly- α -L-glutamic acid and is also dependent partly upon the molecular weight of the polyglutamates.

DETERMINATION OF GLUTAMINE AND GLUTAMIC ACID IN THE BLOOD PLASMA OF CHICKS BY A COMBINED CHROMATOGRAPHIC AND MICROBIOLOGICAL METHOD

Glutamine was separated from glutamic acid by chromatographing deproteinized plasma on a 10-cm column of Dowex 1X8 and by eluting with acetate buffer, pH 4.2. The first portion of eluate, which contained the glutamine but no glutamic acid, was subjected to microbiological assay using Lactobacillus plantarum as a test organism. Recovery of glutamine added to plasma was satisfactory and the precision of the assays conducted was within 4%. Several substances were found to interfere with the microbiological assay but these were eliminated by the chromatographic procedure. The method was extended to the determination of glutamic acid by continued elution of the column with acetate buffer, pH 4.2, fractionation of the eluate, and determination with ninhydrin. Average glutamine and glutamic acid contents of plasma of normal non-fasting chickens were 12.8 and 3.4 mg per 100 ml respectively.

Practical experience in microbiological assays using lactic acid bacteria

The author discusses and gives some details of technique and methods of microbiological determinations based on the use of the lactic acid bacteria. Attention is directed to a simple apparatus for obtaining preparations of the bacterial culture by dry refrigeration and a description is given of an automatic pipette for small amounts. In addition, it is noted that irregularities can arise in the standard curves for a certain number of amino-acid determinations and difficulties which are encountered in the determination of glutamic acid and cystine are also discussed. Finally, the author discusses his experiences with a number of different methods which have been proposed for the determination of vitamins.

Chromatographic Method for the Determination of Glutamic and Aspartic Acid in Mixtures of Different Amino Acids

Summary.On the basis of previously reported works by TURBA and WIELAND a chromatographic method for the quantitative separation and determination of glutamic acid and aspartic acid in a mixture of amino acids has been outlined. The method allows the determination of 5–30 micromols amino acids with the same accuracy as a micro‐Kjeldahl determination. The method is especially apt for series analyses.

A METHOD FOR THE DETERMINATION OF GLUTAMIC ACID IN PROTEINS

A METHOD FOR THE DETERMINATION OF GLUTAMIC ACID IN PROTEINS