基于L-半胱氨酸修饰的锰掺杂ZnS量子点应用于叶酸测定  

Determination of Folic Acid Using Mn^(2+) Doped ZnS Quantum Dots Capped with L-Cysteine

作　　者：占浔寿[1] 商燕[1] 吴芳英[1] 

机构地区：[1]南昌大学化学系,江西南昌330031

出　　处：《分析测试学报》2012年第5期564-569,共6页Journal of Instrumental Analysis

基　　金：国家自然科学基金资助项目(20965006)

摘　　要：以L-半胱氨酸为表面修饰剂制备了稳定性和水溶性均优的ZnS∶Mn2+纳米晶,并应用于叶酸的检测。在pH 7.4的KH2PO4-Na2HPO4缓冲溶液中,叶酸的加入使ZnS∶Mn2+体系的荧光发生猝灭,荧光强度的变化与叶酸浓度呈良好的线性关系,其线性范围为1.0×10-6～7.0×10-5mol.L-1(4.4×10-4～3.1×10-2g.L-1),方法检出限为9.6×10-7mol.L-1(4.2×10-4g.L-1)。该方法用于叶酸片剂和健康人尿液中叶酸的测定,结果满意。采用荧光光谱、紫外可见吸收光谱及X-ray光谱等研究了ZnS∶Mn2+纳米晶及其水溶液的特性,通过热力学参数对叶酸测定的可能机理进行了探讨。Water-soluble L-cysteine-modified-ZnS ∶ Mn2＋ quantum dots（QDs） were prepared in aqueous solution under the room temperature,and characterized by infrared spectrometry,ultraviolet-visible spectrometry,fluorescence spectrometry and X-ray diffraction spectrometry.Based on the fluorescence quenching of ZnS ∶ Mn2＋ QDs caused by folic acid（FA）,the prepared QDs were evaluated as a fluorescence probe for FA detection.Factors affecting the fluorescence detection on FA were studied.Under the optimal conditions,the quenched fluorescence intensity was linear with FA concentration in the range of 1.0×10-6-7.0×10-5 mol·L-1 with correlation coefficient of 0.994.The limit of detection for FA was 9.6×10-7 mol·L-1.The proposed method was applied in the determination of folic acid in folic acid tablet and urine samples with satisfactory results.The mechanism for detection of FA was also investigated.

关 键 词：叶酸 ZnS∶Mn2+ 荧光测定 L-半胱氨酸 

分 类 号：O657.3[理学—分析化学]