Analysis Of Amino Acid Mixtures Research Articles

Indicators of blood biochemical analysis in PKU patients being on amino acid mixtures substitute nutrition

Topicality. Phenylketonuria is a congenital pathology of amino acid metabolism, which is a rare (orphan) disease. Depending on the regions of the world and the ethnic origin of the inhabitants, its prevalence can vary from 1/2600 to 1/200000. Phenylketonuria is caused by a deficiency of liver enzyme phenylalanine hydroxylase, which catalyzes the hydroxylation of phenylalanine, resulting in the formation of tyrosine. Enzyme deficiency leads to hyperphenylalaninemia, and in the absence of adequate therapeutic measures will lead to profound and irreversible disability of the patient.Aim. To conduct a comparative analysis of amino acid mixtures “Nutri-2”, “Nutri-3”, “PAM-2” and “PAM-3”, as well as to determine the biochemical parameters of the blood of four groups of patients on these diets according to their age needs.Materials and methods. On the basis of Kharkiv interregional specialized medical-genetic center of rare (orphan) diseases, treatment of phenylketonuria with the use of amino acid mixtures was introduced and further biochemical analysis of patients’ blood was performed. The results of biochemical parameters of blood of four groups of heterosexual and different-aged patients on different amino acid mixtures were taken for the study. The study involved 16 patients of different sexes aged 4 to 29 years.Results and discussion. The determined values of most biochemical markers in patients with PKU were within the reference values. In some patients taking PAM-2, minor changes were observed, which were reflected in increased urea content and activity of aspartate aminotransferase, lactate dehydrogenase and alkaline phosphatase outside the upper limit of normal.Conclusions. New therapeutic foods have more balanced nutritional composition, developed according to modern dietary recommendations, which is confirmed by stable biochemical parameters of the blood of patients with phenylketonuria.

Analysis of Amino Acid Mixtures by Voltammetric Electronic Tongues and Artificial Neural Networks

AbstractA new voltammetric electronic tongue formed with graphite‐epoxy composite electrodes which were modified with metal‐oxide nanoparticles is presented for the quantification of tryptophan, tyrosine and cysteine aminoacid mixtures. The signals were obtained by cyclic voltammetry, and data was processed using two different chemometric techniques, artificial neural networks and partial least squares regression, for comparison purposes. Before performing artificial neural networks data was compressed by fast Fourier transform or discrete wavelet transform. The best results were attained using artificial neural networks with previous fast Fourier transform compression of the data with a normalized root‐mean‐square error of 0.032 (n=15) for the external test subset. The present method shows results comparable to other similar approaches, but with a much easier sampling process for the training set and new electrode modifiers to form the voltammetric sensors.

Spectrofluorometric analysis of amino acid mixtures: Implications for future space missions

Efficient detection of organic molecules is fundamental for the success of future life detection missions. Spectrofluorometric analysis is one of the many techniques that may be used to detect organic molecules in extraterrestrial settings. A particularly important class of organic molecules to target is the amino acids on which all terrestrial life depends. This study aims to identify the optimum fluorescence excitation and emission wavelengths for 17 amino acid standards to examine the effects of amino acid concentrations, mixtures and fluorescence quenching. The results and interpretations can guide the design and operation of life detection protocols on future space missions.

Amino Acids Analysis by MALDI Mass Spectrometry Using Carbon Nanotube as Matrix

Twenty common amino acids have been analyzed successfully by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using carbon nanotubes as matrix. From the spectra, little or no background interference or fragmentation of the analytes has been observed. This method was also applied to the analysis of amino acid mixture successfully. Carbon nanotubes have some features such as large surface area to disperse the analyte molecules sufficiently and prevent the sample aggregation and strong ultraviolet absorption to transfer energy easily to the analyte molecules. The present method has potential application for the rapid and sensitive analysis of amino acids and their mixture

One‐dimensional TOCSY 1H NMR experiments on adducts of amino acid esters with cobalt(III) tetramethylchiroporphyrin. Prospects for the analysis of amino acid mixtures

AbstractCobalt(III) tetramethylchiroporphyrin, CoCl(TMCP), is a useful chiral shift reagent for structure attribution, absolute configuration assignment and enantiomeric excess determination of amino acid methyl esters by 1H NMR spectroscopy. However, it has two axial sites available for amine coordination, a structural feature which generates n(n + 1)/2 diastereomeric species and n2 distinct spin systems from a mixture of n amino ester enantiomers, making the analysis of complex amino acid samples exceedingly difficult by classical 1‐D or 2‐D NMR methods when n > 3. The 1‐D TOCSY experiment is shown to be a powerful tool for the selective excitation and detection of every single component of a mixture of four amino acid methyl esters bound to CoCl(TMCP): those of(S)‐Leu, (S)‐Asp, (R)‐Asp and (S)‐Glu, for example. The potential utility of this methodology for the determination of amino acid enantiomers in carbonaceous meteorites or other extraterrestrial samples is suggested. Copyright © 2002 John Wiley & Sons, Ltd.

Gas chromatography—chemical ionization mass spectrometry in amino acid analysis of pyoverdins

The application and advantages of positive chemical ionization with methane [CI(CH 4)] for gas chromatography-mass spectrometry (GC-MS) of perfluoroacyl amino acid alkyl esters are discussed. All investigated amino acids show [M + H] +, [M + C 2H 5] +, and [(M + H) − C 3H 6] +. By a comparison of the electron ionization (EI) and CI(CH 4) mass spectra the analysis of amino acid mixtures by GC-MS will give reliable results also in the case of isomeric compounds or of (partial) decomposition during analysis.

Analysis of amino acid mixtures by plasma desorption mass spectrometry

AbstractPlasma desorption mass spectrometry (PDMS) was investigated as a means of analysing mixtures of three, four and five amino acids in both positive‐ and negative‐ion modes. Fifteen mixtures were tested; each mixture contained equimolar amounts of selected amino acids. The PD mass spectra exhibited MH+ and [M – H]− molecular ions for all the aminoacids with different desorption–ionization yields. The spectra were more easily interpreted in the negative‐ than the positive‐ion mode. The desorption order of the amino acids was progressively established by comparing the molecular ion desorption–ionization yields for each mixture. This desorption order was well correlated in both the positive‐ and negation‐ion modes with the acid–base thermodynamic data for the amino acids in the gas phase. This observation gives some insight into the desorption–ionization mechanisms under PDMS conditions.

Measurement of plasma and urine amino acids by high-performance liquid chromatography with electrochemical detection using phenylisothiocyanate derivatization

The use of reversed-phase liquid chromatography (LC) with pre-column derivatization for the analysis of amino acid mixtures is becoming established as a possible cheaper alternative to commercial amino acid analysers. The available derivatization procedures all have disadvantages when applied to clinical samples, partly due to the interferences found with body fluids when ultraviolet or fluorescence detection is used. An LC method is described for the separation of amino acids in blood or urine, using pre-column derivatization with phenylisothiocyanate (PITC), gradient elution and electrochemical detection. The use of electrochemical detection of PITC derivatives virtually eliminates interferences and enables the secondary amino acids to be measured. Examples are shown of normal urine and plasma and samples from patients with cystinuria and maple syrup urine disease.

Simultaneous kinetic determinations with the kalman filter

The linear Kalman filter is successfully applied to the processing of data for simultaneous kinetic determinations. The Kalman filter offrs all of the advantages of linear least squares over traditional methods of data processing, but is simpler and more efficient than batch-mode least squares. The viability of the Kalman filter is demonstrated with synthetic data and it is then applied to the analysis of amino acid mixtures by their reaction with trinitrobenzenesulfonic acid. Mixtures of glycine and asparagine are successfully analyzed even though their pseudeo-first-order rate constants differ by a factor of only 2.5. The potential of the Kalman filter for real-time application is discussed.

Response amplification of histidine in gas—liquid chromatographic analysis of amino acid mixtures

Response amplification of histidine in gas—liquid chromatographic analysis of amino acid mixtures

Gas chromatography of amino acid derivatives.

Extensive studies have been made in attempts to adapt the gas-liquid chromatography technique to amino acids analysis. Since the discovery of the gas-liquid chromatograph, the idea of using it for amino acids analysis has been enthusiastically expounded because of its great potential in providing a means by which qualitative and quantitative analysis of amino acids can be achieved quickly and accurately in comparison with other techniques currently in use. Excellent automated procedures are known at the present for analysis of amino acid mixtures. With ion exchange chromatography columns, mixtures of amino acids, in the amount of 10−7 mole each, can be analyzed. The disadvantages of this system, however, are the time required (up to 24 h in some cases), the cost of the instrument, and the relative complexity of the operation.KeywordsAmino Acid AnalysisElectron Capture DetectorAmino Acid DerivativeGlycol AdipateEthylene Glycol AdipateThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

La radioactivité au service de l'analyse chimique

A description is given of various methods of analysis which make use of radioactivity : Method of direct activation (determination of manganese in an aluminium alloy). Use of exchange reactions (determination of a mixture of chlorides, bromides, iodides). Determination making use of the transparence to neutrons (e.g., determination of boron in boron carbide). Determination by means of a radioactive reagent (analysis of amino-acid mixtures). Dilution method (determination of potassium). Etc.