28 biogenic amines and amino acids were quantitated in red French wines over a 14 year period by micellar electrokinetic chromatography separation and laser-induced fluorescence detection of ...fluorescein thiocarbamate derivatives. The grapes were grown in the same wine yard, under identical conditions, and the wines were made under fixed standard procedures. A pattern of evolution of amines and amino acids during wine aging is given. Principal component analysis indicates some correlations between the different amino acids and biogenic amines. A discussion on the behavior of amino acids during wine aging is presented.
Two water network optimization methods are presented. Both can be utilised to establish, without detailed design, whitewater network configurations that would minimize fresh water requirements and ...waste-water rejects while respecting critical contamination constraints. The essentially graphic pinch-type analysis is partially automated; it is only applicable to one contaminant system. Linear programming appears to be a more powerful tool because it can be applied simultaneously to several contaminants to be removed and fine fibers to be retained in the system while fresh water consumption is minimized. It is fully automated and particularly well adapted to large size problems. Both methods have been applied to industrial case studies with interesting results. In the case of the water network of the alkaline zone of a de-inking plant no fresh water consumption reduction was obtained, but it was shown that network rearrangement could eliminate the need for a filtration step. In the case of the complete whitewater network of an integrated newsprint mill, it was shown that it is possible to reduce the fresh water consumption by two thirds.
In recent papers, we presented a new analytical method for thiol quantification in serum. It is based on the use of capillary electrophoresis and laser-induced fluorescence to analyze thiol ...6-iodoacetamidofluoresceine (IAF) derivatives. Quantitative results of homocysteine, glutathione, cysteine–glycin, and cysteine were shown (Clin. Chem. 45 (1999) 412). A comprehensive comparison of the quantitation of homocysteine in serum, using high-performance liquid chromatography/conventional fluorescence detection and fluorescence polarization immunoassay was also used (E. Caussé et al., Electrophoresis 21 (2000) 2074). Sample preparation prior to derivatization with IAF had never been investigated. In this work we present the results of quantitation of thiols in serum and plasma with three different anticoagulants widely used: ethylenediaminetetraacetic acid (EDTA), heparin, and sodium citrate. We show that serum and EDTA plasma gave the same results. Then serum protein precipitations by acetonitrile, acetone, sulfosalicylic acid, perchloric acid and trichloracetic acid, prior to derivatization by IAF, were also investigated. Their influence on the concentrations of the thiols were determined. Sulfosalicylic acid and acetonitrile precipitations are well adapted, whereas acetone cannot be used.
When the rhizosphere is starved of nitrogen, the soil bacteria Rhizobium are able to infect legume roots and invade root nodules, where they can fix atmospheric nitrogen. Nod boxes, the nod gene ...promoters located on the rhizobial symbiotic plasmid, are activated by means of flavonoids present in the legume root exudates, leading to the synthesis of lipochitooligomers: the Nod factors. Several recent works pointed out the importance of rhizobial surface polysaccharides in establishing the highly specific symbiosis between rhizobia and legumes. Lipopolysaccharides (LPSs) exhibit specific active roles in the later stages of the nodulation processes, such as the penetration of the infection thread into the cortical cells or the setting up of the nitrogen-fixing phenotype. The study reported here concerns the structural modifications affecting surface (lipo)polysaccharides when Sinorhizobium sp. NGR234 strains are grown with nod gene induction under nitrogen starvation. In the absence of induction, NGR234 only produces fast-migrating LPSs. When cultured in the presence of flavonoids, the same strain produces large quantities of a high-molecular-weight rhamnose-rich lipopolysaccharide (RLPS). Because the synthesis of this compound seems to be coded by the symbiotic plasmid under direct or indirect gene induction by flavonoids, this RLPS is thought to be biologically relevant.
The separation of organic and inorganic acids was performed by capillary zone electrophoresis using indirect UV detection. Optimum conditions for the separation of 11 anions were investigated. This ...method was applied for the simultaneous determination of organic and inorganic anions in foods and beverage samples. The relative standard deviation (R.S.D.) for the analysis of anions was less than 1% for the migration time and 1–4% for the peak area (
n=18). The detection limits was from 0.006 to 1.072 mg/l for the 11 anions. This newly developed method is rapid, sensitive and quantitative and can be readily applied to real food and beverage samples for quantitative analysis.
Asymmetric dimethyl-
l-arginine (ADMA) is a naturally occurring analogue of
l-arginine (
l-Arg), the substrate of nitric oxide synthase (NOS). ADMA is a potent endogenous inhibitor of NOS and ...accumulates in the plasma of patients with renal failure, with peripheral arterial occlusive disease or with clinically asymptomatic hypercholesterolemia. We measured circulating concentrations of
l-arginine, symmetric and asymmetric dimethylarginine (SDMA and ADMA, respectively) in human serum. We developed a new method for the rapid determination of these molecules using capillary electrophoresis and laser-induced fluorescence (CE–LIF). All methylated arginines were labeled with fluorescein isothiocyanate (FITC) prior to analysis. Under the capillary electrophoresis (CE) conditions used, methylated arginine derivatives were well separated, with a migration time of around 10 min. These migration times were smaller than the ones of other amino acids which do not have the same charge at pH 10. Consequently, such basic amino acids were well separated from most of the other amines or amino acids. Moreover, CE allowed one to separate all the analogues of fluorescein thiocarbamyl–arginine. The results indicated that CE–LIF is useful as a selective, rapid, cheap and sensitive tool for the determination of methylated arginine products. This new technology might appreciate the endogenous substrate for NO synthase and facilitate the knowledge of the physiological and pathophysiological regulation of NO synthesis.
Laser-induced fluorescence (LIF) detection is now a well-known sensitive and selective detection mode for capillary electrophoresis (CE) analysis. It has been shown to be 100- to 10 0000-times more ...sensitive than UV detection and little work has been done using LIF in conjunction with high-performance liquid chromatography (HPLC). The need for greater resolution and higher sensitivity for the analysis of anthracyclines (fluorescent chemotherapic drugs), prompted us to compare CE–LIF and HPLC–LIF, for the detection of these substances. CE–LIF sensitivity based on quantity of anthracycline injected is 50-times greater than that obtained with HPLC–LIF, because of the injected sample volume. Analysis of daunorubicin in Kaposy sarcoma tumors and in plasma are presented. The decrease of the concentration of daunorubicin in the tumor and in the plasma following time show the same behavior, indicating identical concentrations of the anthracycline in both samples.
A ball-lens laser-induced fluorescence detector based on the conventional collinear arrangement is described for use with capillary electrophoresis. It allows better mechanical tolerances for ...capillary adjustment in front of the laser beam. Its sensitivity is equal to that of the conventional collinear arrangement. Micellar electrokinetic chromatographic determination of biogenic amines in dairy products is described as an application of this detector.
Over the past few years, a large number of studies have been prepared that describe the analysis of peptides and proteins using capillary electrophoresis (CE) and laser‐induced fluorescence (LIF). ...These studies have focused on two general goals: (i) development of automatic, selective and quick separation and detection of mixtures of peptides or proteins; (ii) generation of new methods of quantitation for very low concentrations (nm and subnanomolar) of peptides. These two goals are attained with the use of covalent labelling reactions using a variety of dyes that can be readily excited by the radiation from a commonly available laser or via the use of noncovalent labelling (immunoassay using a labelled antibody or antigen or noncovalent dye interactions). In this review article, we summarize the works which were performed for protein and peptide analysis via CE‐LIF.
Capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) was used to analyze a 50-μl sample of cerebrospinal fluid from leukaemic children treated with high doses of methotrexate. ...Free amino acids and primary amines are labelled with fluorescein isothiocyanate prior to analysis. Electropherograms containing more than 50 peaks were obtained in less than 22 min. Twenty-one peaks were identified, and 19 were quantitated. Observed differences in individual amino acid levels are compared with healthy reference values. The results indicate that CE-LIF is useful as a selective, rapid and sensitive tool for the determination of free amino acids and amines in clinical biology studies.
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