Optimization of separation and detection of 6-aminoquinolyl derivatives of amino acids by using reversed-phase liquid chromatography with on line UV, fluorescence and electrochemical detection

Pappa-Louisi, A.; Nikitas, P.; Agrafiotou, P.; Papageorgiou, A.

doi:10.1016/j.aca.2007.04.044

Cited by 47 publications

(27 citation statements)

References 23 publications

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“…Alternatively, linear and nonlinear gradients can be approximated by stepwise gradients consisting of p equidistant steps, where p is a relatively great number. Cela et al [29,30] propose p = 11, however in a recent paper we found that good results are obtained when p is of the order of 100 [31]. Under this approximation, the retention time, t R , is calculated from [32] …”

Section: Gradients Of U At Constant Tmentioning

confidence: 94%

Combined effect of temperature and organic modifier concentration on the retention under single mode gradient conditions in reversed‐phase HPLC

Pappa-Louisi¹,

Nikitas²,

Zisi³

et al. 2008

J of Separation Science

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The combined effect of temperature, T, and organic modifier concentration, phi, on the retention under gradient conditions in RPLC is studied by considering, both theoretically and experimentally gradients, of phi at constant T and gradients of T at constant phi. Two approaches are examined: in the first approach the prediction of the elution time of a sample solute is based on the isocratic/isothermal properties of this solute. The second approach is based on a direct fitting procedure of a proper retention model to 2-D isocratic/T-gradient or isothermal/phi-gradient retention data. These approaches were tested using alkylbenzes in eluting systems modified by ACN. We found that both approaches can give excellent predictions under certain prerequisites. However, the first approach exhibits the notable advantage that it can be used effectively to predict retention times under any kind of phi-gradients at constant T or T-gradients at constant phi. The second approach has the advantage that it is relatively simple but its applicability is very restricted since its predictions are satisfactory only if the gradients are of the same kind with those used in the fitting procedure and the conditions lie within those used for fitting.

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Section: Gradients Of U At Constant Tmentioning

confidence: 94%

Combined effect of temperature and organic modifier concentration on the retention under single mode gradient conditions in reversed‐phase HPLC

Pappa-Louisi¹,

Nikitas²,

Zisi³

et al. 2008

J of Separation Science

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show abstract

“…The second issue can be overcome by using detection methods such as amperometric detection [55], or post-column derivatization [56]. Alternatively, pre-column derivatization can be used to improve both chromatographic behavior and detection, but it requires additional steps during sample preparation [57–59]. …”

Section: In Vivo Measurement Of Carnosinementioning

confidence: 99%

Detoxification of aldehydes by histidine-containing dipeptides: From chemistry to clinical implications

Xie

Baba

Sweeney

et al. 2013

Chemico-Biological Interactions

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Aldehydes are generated by oxidized lipids and carbohydrates at increased levels under conditions of metabolic imbalance and oxidative stress during atherosclerosis, myocardial and cerebral ischemia, diabetes, neurodegenerative diseases and trauma. In most tissues, aldehydes are detoxified by oxidoreductases that catalyze the oxidation or the reduction of aldehydes or enzymatic and nonenzymatic conjugation with low molecular weight thiols and amines, such as glutathione and histidine dipeptides. Histidine dipeptides are present in micromolar to millimolar range in the tissues of vertebrates, where they are involved in a variety of physiological functions such as pH buffering, metal chelation, oxidant and aldehyde scavenging. Histidine dipeptides such as carnosine form Michael adducts with lipid-derived unsaturated aldehydes, and react with carbohydrate-derived oxo- and hydroxy- aldehydes forming products of unknown structure. Although these peptides react with electrophilic molecules at lower rate than glutathione, they can protect glutathione from modification by oxidant and they may be important for aldehyde quenching in glutathione-depleted cells or extracellular space where glutathione is scarce. Consistent with in vitro findings, treatment with carnosine has been shown to diminish ischemic injury, improve glucose control, ameliorate the development of complications in animal models of diabetes and obesity, promote wound healing and decrease atherosclerosis. The protective effects of carnosine have been linked to its anti-oxidant properties, it ability to promote glycolysis, detoxify reactive aldehydes and enhance histamine levels. Thus, treatment with carnosine and related histidine dipeptides may be a promising strategy for the prevention and treatment of diseases associated with high carbonyl load.

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“…A number of techniques for AA analysis have been developed [3], including nuclear magnetic resonance [4][5][6], liquid chromatography coupled with optical detection [7,8], gas chromatography-mass spectrometry [9,10], liquid chromatography-mass spectrometry (LC-MS) [11], and capillary electrophoresis [12,13]. Among the varieties of techniques, MS plays an important role in the analysis of protein and metabolite from complex biological samples due to the high sensitivity and selectivity [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Improving detection sensitivity of amino acids in thyroid tissues by using phthalic acid as a mobile phase additive in hydrophilic interaction chromatography-electrospray ionization-tandem mass spectrometry

Guan

Cao

et al. 2015

Analytica Chimica Acta

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Optimization of separation and detection of 6-aminoquinolyl derivatives of amino acids by using reversed-phase liquid chromatography with on line UV, fluorescence and electrochemical detection

Cited by 47 publications

References 23 publications

Combined effect of temperature and organic modifier concentration on the retention under single mode gradient conditions in reversed‐phase HPLC

Combined effect of temperature and organic modifier concentration on the retention under single mode gradient conditions in reversed‐phase HPLC

Detoxification of aldehydes by histidine-containing dipeptides: From chemistry to clinical implications

Improving detection sensitivity of amino acids in thyroid tissues by using phthalic acid as a mobile phase additive in hydrophilic interaction chromatography-electrospray ionization-tandem mass spectrometry

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