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Wykorzystanie derywatyzacji w analizie próbek biologicznych na zawartość aminotioli techniką wysokosprawnej chromatografii cieczowej z detekcją UV-Vis

Głowacki R.

Wiadomości Chemiczne

2009

[Z] 63, 11-12

1049-1071

Thiols are chemically and biochemically very active components of the sulfur cycle of the natural environment. Low molecular-mass thiols, such as homocysteine, cysteine, cysteinylglycine and glutathione are critical cellular components that play numerous roles in metabolism and homeostasis, and are important in a variety of physiological and pathological processes [1, 2]. Plasma thiols are being investigated as potential indicators of health status and disease risk [3.8]. Because of high affinity to oxidation low-molecular-mass thiols exist in biological samples mostly as symmetrical, unsymmetrical and protein-bound disulfides. Thus, determination of total thiol content must comprise disulfide bond disruption step. A reducing agent is necessary both for the reduction of the sulfide bonds and to keep the thiol in a reduced form until start of derivatization. Most of thiols lack the structural properties necessary for the production of signals compatible with common HPLC detectors, such as UV absorbance and fluorescence. Therefore, an analyst must resort to derivatization for signal enhancement and labile sulfhydryl group blocking if fluorescence or UV-Vis detection methods are employed. Ultraviolet detection is less specific and less sensitive than fluorescence one, nevertheless, its sensitivity is sufficient for detection and quantitation of endogenous and exogenous thiols in biological samples in physiological and pathological conditions. Moreover, equipment for HPLC-UV analysis is often a part of an existing, standard instrumentation in hospital laboratories and staff is usually well experienced in its use. All methods, except those based on electrochemical and tandem-mass spectrometry detection, depend on pre- or post-column derivatization of thiols. Useful reagents must form thiol derivatives with sufficient absorption and/or fluorescent yield to measure thiols at trace concentrations. Furthermore, the ideal reagent should show no absorption and should react rapidly and specifically with thiols to form stable products. Numerous reagents are available for the thiol derivatization. A majority of the reagents can be classified by type of the reactive moiety into three categories: activated halogen compounds, disulfides, and compounds possessing maleimide moiety, and are reviewed with some experimental details in excellent works [36.41].