Rapid and sensitive determination of free thiols by capillary zone electrophoresis with near‐infrared laser‐induced fluorescence detection using a new BODIPY‐based probe as labeling reagent |
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Authors: | Li‐Yun Zhang Feng‐Qin Tu Xiao‐Feng Guo Hong Wang Peng Wang Hua‐Shan Zhang |
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Institution: | 1. Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, P. R. China;2. Hubei Entry Exit Inspect & Quarantine Bur PRC, Ctr Technol, Wuhan, P. R. China |
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Abstract: | A CZE with near‐infrared (NIR) LIF detection method has been developed for the analysis of six low molecular weight thiols including glutathione, homocysteine, cysteine, γ‐glutamylcysteine, cysteinylglycine, and N‐acetylcysteine. For this purpose, a new NIR fluorescent probe, 1,7‐dimethyl‐3,5‐distyryl‐8‐phenyl‐(4'‐iodoacetamido)difluoroboradiaza‐s‐indacene was utilized as the labeling reagent, whose excitation wavelength matches the commercially available NIR laser line of 635 nm. The optimum procedure included a derivatization step of the free thiols at 45°C for 25 min and CZE analysis conducted within 14 min in the running buffer containing 16 mmol/L pH 7.0 sodium citrate and 60% v/v ACN. The LODs (S/N = 3) ranged from 0.11 nmol/L for N‐acetylcysteine to 0.31 nmol/L for γ‐glutamylcysteine, which are better than or comparable to those reported with other derivatization‐based CE‐LIF methods. As the first trial of NIR CE‐LIF method for thiol determination, the practical application of the proposed method has been validated by detecting thiols in cucumber and tomato samples with recoveries of 96.5–104.3%. |
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Keywords: | 1 7‐Dimethyl‐3 5‐distyryl‐8‐phenyl‐(4'‐iodoacetamido)difluoroboradiaza‐s‐indacene Capillary electrophoresis Near‐infrared laser‐induced fluorescence Thiols |
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