Reduced form of β-nicotinamide adenine dinucleotide(NADH)and its oxidized form(NAD~+)are the main cofactors involved in more than 300 dehydrogenase reactions.NAD~+ is one of the important oxidizing agent for the oxidation of alcohol,aldehyde and ketones.Similarly,NADH has been used for the treatment of Alzheimer and Parkinson's diseases.Herein,we have reported synthesis of graphene flakes by electrochemical exfoliation of graphite in sodium tungstate solution.It was found that tungstate(WO_4~(2-))and hydroxyl(OH~-)ions were intercalated into graphite layers and enabled the production of graphene flakes.As-obtained graphene flakes were characterized by UV-Visible(UV-Vis),Fourier transform infrared(FT-IR),Raman,Field emission scanning electron microscopy(FE-SEM),Energy dispersive X-ray(EDX)and High-resolution transmission electron microscopies(HR-TEM).FT-IR,Raman and EDX analysis were confirmed that tungstate(WO_4~(2-))ions were present on the surface of graphene flakes.Moreover,graphene-WO_4~(2-)(Gr-W)dispersion was prepared by probe-sonication to form a thin-film on the surface of glassy carbon electrode(Gr-W/GCE).Interestingly,Gr-W modified GCE reduced the overpotentials of NADH oxidation and NAD~+ reduction.This new senor was also showed linear responses for NADH and NAD~+ from 10-270 μM and 100-500 μM,respectively.Furthermore,the selectivity of the Gr-W/GCE was tested in the presence of L-tyrosine,Lisoleucine,L-alanine,glutathione,dopamine(DA),ascorbic acid(AA),uric acid(UA),oxalic acid(OA),glucose,hydrogen peroxide(H2O2),acetaminophen(PA),potassium chloride(KCl)and sodium chloride(NaCl).It was found that selective detection of both NADH and NAD~+ could be achieved by using Gr-W/GCE.Finally,the real application of the sensor was demonstrated by accurately detecting spiked NADH concentrations in human blood serum.The recovery analysis was also confirmed that Gr-W/GCE could be useful to detect NADH in biological samples.
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机译：β-烯酰胺腺苷二核苷酸（NADH）及其氧化形式（NAD〜+）的还原形式是参与300多种脱氢酶反应的主要辅助因子。NAD〜+是氧化酒精，aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde和aldehyde and aldehyde and and aldehyde and and的氧化剂。相似，NADH已用于治疗阿尔茨海默氏症和帕金森氏症的疾病。在这里，我们报道了通过在硫顿硫酸钠溶液中的电化学去角质来合成石墨烯薄片的。将羟基（OH〜-）离子插入石墨层并启用了石墨烯薄片的产生。被带有紫外线的石墨烯薄片以UV-可见度（UV-VIS），傅立叶变换红外（FT-IR（FT-IR），RAMAN，RAMAN，RAMAN，RAMAN，现场发射）表征扫描电子显微镜（FE-SEM），能量色散X射线（EDX）和高分辨率透射电子显微镜（HR-TEM）.FT-IR，RAMAN和EDX分析已证实Tungstate（WO_4〜（2-））离子存在于石墨烯薄片的表面上。此外，石墨烯-wo_4〜（2-）（gr-w）通过探针传声制备分散剂，以在玻璃碳电极（GR-W/GCE）表面形成薄膜（GR-W/GCE）。 NADH氧化和nAD〜+还原。该新的新人还显示了NADH和NAD〜+的线性响应，分别为10-270μm和100-500μm。furthermore，GR-W/GCE的选择性在IN中测试L-酪氨酸，Lisolecine，L-丙氨酸，谷胱甘肽，多巴胺（DA），抗坏血酸（AA），尿酸（UA），草酸（OA），葡萄糖，葡萄糖，过氧化氢（H2O2），乙酰氨基酚（PA）（PA） ，氯化钾（KCl）和氯化钠（NACL）。发现可以通过使用GR-W/GCE来实现NADH和NAD〜+的选择性检测。通过精确检测传感器的实际应用，通过准确检测来证明传感器的真实应用恢复分析也证实了GR-W/GCE在生物样品中检测NADH可能是有用的。
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