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.

Capillary electrophoresis tandem mass spectrometry determination of glutamic acid and homocysteine's metabolites: Potential biomarkers of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects both lower and upper motor neurons, leading to muscle atrophy, paralysis, and death caused by respiratory failure or infectious complications. Altered levels of homocysteine, cysteine, methionine, and glutamic acid have been observed in plasma of ALS patients. In this context, a method for determination of these potential biomarkers in plasma by capillary electrophoresis tandem mass spectrometry (CE-MS/MS) is proposed herein. Sample preparation was carefully investigated, since sulfur-containing amino acids may interact with plasma proteins. Owing to the non-thiol sulfur atom in methionine, it was necessary to split sample preparation into two methods: i) determination of homocysteine and cysteine as S-acetyl amino acids; ii) determination of glutamic acid and methionine. All amino acids were separated within 25min by CE-MS/MS using 5molL-1 acetic acid as background electrolyte and 5mmolL-1 acetic acid in 50% methanol/H2O (v/v) as sheath liquid. The proposed CE-MS/MS method was validated, presenting RSD values below 6% and 11% for intra- and inter-day precision, respectively, for the middle concentration level within the linear range. The limits of detection ranged from 35 (homocysteine) to 268nmolL-1 (glutamic acid). The validated method was applied to the analysis of plasma samples from a group of healthy individuals and patients with ALS, showing the potential of glutamic acid and homocysteine metabolites as biomarkers of ALS.

Hallazgos neurorradiológicos en aminoaciduria glutárica tipo I: informe de dos casos / Neuroradiologic findings in glutaric aminoaciduria type I

Se informan los hallazgos neurradiológicos de dos pacientes pediátricos con aminoaciduria glutárica tipo I (AG-I), a quienes se les realizó tomografía de cabeza y, sólo a uno, estudio de imagen de resonancia magnética. El diagnóstico bioquímico se llevo a cabo mediante la medición de ácido glutártico libre en orina, así como por cromatografía de gas para determinar la actividad enzimática del glutaril Co-A deshidrogenasa en los leucocitos. El retardo en la mielinización, con su consecuente disminución generalizada de la sustancia blanca, es característico de varias enfermedades metabólicas; las evidencias de las alteraciones de disgénesis cerebral se obtienen básicamente mediante estudios de neuroimagen. Se debe sospechar una probable enfermedad hereditaria del metabolismo como AG-I cuando se tenga un paciente pediátrico con retraso psicomotor, alteraciones motoras extrapiramidales o macrocrania, en el cual se obtengan los siguientes hallazgos neurorradiológicos: atrofia bilateral de la fosa temporal asociada con áreas hipodensas difusas en la sustancia blanca, ligera atrofia o pérdida del volumen de los ganglios basales, hipoplasia del vermis del cerebelo y ocasionalmente colección subdural de líquido.