基于糊精碳量子点荧光信号“关-开”测定L-抗坏血酸的研究
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摘要
通过水热法,一步合成糊精发光碳量子点(CQDs),其荧光量子产率为8.3%。研究发现,在pH=3.10的B-R缓冲介质中,KMnO_4能使该CQDs荧光发生显著猝灭,荧光信号"关闭";加入L-抗坏血酸后,由于L-抗坏血酸的还原性,将KMnO_4从CQDs表面移除下来,使CQDs的荧光信号恢复,体系的荧光信号处于"打开"状态。据此提出了"关-开"型荧光探针高灵敏检测L-抗坏血酸的方法。对反应的机理进行初步探讨,考察了各种反应条件。在优化的实验条件下,CQDs的荧光恢复值与L-抗坏血酸的浓度在6.0×10~(-7)～2.0×10~(-5 )mol·L~(-1)范围内呈良好线性关系,检出限(3S/N)为4.4×10~(-7 )mol·L~(-1)。方法用于样品中L-抗坏血酸含量的检测,结果满意。
A one-step hydrothermal method was developed for the preparation of carbon quantum dots(CQDs)with strong fluorescence by using dextrin as precursors.The fluorescence quantum yield of dextrin CQDs was 8.3%.The experiments indicated that in pH=3.10 B-R buffer solution,when KMnO_4 was added in CQDs solution,the fluorescence of CQDs was quenched,and the fluorescence signal of the system was in the"off"state.In the presence of L-ascorbic acid,the fluorescence of CQDs was recovered because KMnO_4 preferred to react with L-ascorbic acid,which results in the departure of KMnO_4 from the surface of the CQDs,and the fluorescence signal of the system was"open".The degree of recovery of CQDs fluorescence intensity was proportional to the L-ascorbic acid concentration,which provided a new method for the detection of L-ascorbic acid with high sensitivity and selectivity based on the fluorescence quenching recovery properties of CQDs.The mechanism was studied,and the reaction conditions were optimized.Under optimal conditions,the recovered fluorescence of CQDs was linearly related with the L-ascorbic acid concentration in the range 6.0×10~(-7) to 2.0×10~(-5 )mol·L~(-1),the detection limit was 4.4×10~(-7 )mol·L~(-1).The present method was applied for the detection of L-ascorbic acid in samples with satisfactory results.
A one-step hydrothermal method was developed for the preparation of carbon quantum dots(CQDs)with strong fluorescence by using dextrin as precursors.The fluorescence quantum yield of dextrin CQDs was 8.3%.The experiments indicated that in pH=3.10 B-R buffer solution,when KMnO_4 was added in CQDs solution,the fluorescence of CQDs was quenched,and the fluorescence signal of the system was in the"off"state.In the presence of L-ascorbic acid,the fluorescence of CQDs was recovered because KMnO_4 preferred to react with L-ascorbic acid,which results in the departure of KMnO_4 from the surface of the CQDs,and the fluorescence signal of the system was"open".The degree of recovery of CQDs fluorescence intensity was proportional to the L-ascorbic acid concentration,which provided a new method for the detection of L-ascorbic acid with high sensitivity and selectivity based on the fluorescence quenching recovery properties of CQDs.The mechanism was studied,and the reaction conditions were optimized.Under optimal conditions,the recovered fluorescence of CQDs was linearly related with the L-ascorbic acid concentration in the range 6.0×10~(-7) to 2.0×10~(-5 )mol·L~(-1),the detection limit was 4.4×10~(-7 )mol·L~(-1).The present method was applied for the detection of L-ascorbic acid in samples with satisfactory results.
引文
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[14]任岗,马红燕,田锐,等.盐酸多西环素与碳量子点相互作用的荧光猝灭效应[J].分析试验室,2016,35(3):305-308.
[2]易凌亚,黎红杨,丽君.枸杞碳量子点的制备及氮修饰对荧光的影响[J].化学研究与应用,2017,29(4):529-532.
[3]Zhang R,Chen W.Nitrogen-doped carbon quantum dots:Facile synthesis and application as a“turn-off”fluorescent probe for detection of Hg2+ ions[J].Biosens Bioelectron,2014,55:83-90.
[4]李晓东.磷铋钼蓝分光光度法测定水果、蔬菜及饮料中L-抗坏血酸[J].理化检验:化学分册,2018,54(5):579-583.
[5]Xu Y L,Niu X Y,Chen H,et al.Switch-on fluorescence sensor for ascorbic acid detection based on MoS2 quantum dots-MnO2 nanosheets system and its application in fruit samples[J].Chin Chem Lett,2017,28(2):338-344.
[6]陈沛金,颜治,涂小珂,等.高效液相色谱法测定化妆品中的维生素C及其衍生物[J].色谱,2015,33(7):771-776.
[7]吴雄志,王立红,吕晓惠.鲁米诺-溴酸钾体系增敏化学发光法测定抗坏血酸[J].分析试验室,2010,29(6):101-104.
[8]Jorge L Cholula-Díaz,DianaLomelí-Marroquín,bidhanPramanick.synthesis of colloidal silver nanoparticle clusters and their application in ascorbic acid detection by sers[J].Colloids Surf B,2018,163:329-335.
[9]Wu T,Guan Y,Ye J.Determination of flavonoids and ascorbic acid in grapefruit peel and juice by capillary electrophoresis with electrochemical detection[J].Food Chem,2007,100(4):1573-1579.
[10]Dan yang Ji,Ya hui Du,Hongmin Meng,et al.A novel colorimetric strategy for sensitive and rapid sensing of ascorbic acid using cobalt oxyhydroxide nanoflakes and 3,3′,5,5′-tetramethylbenzidine[J].Sens Actuators B,2018,256(3):512-519.
[11]Long Y M,Zhou C H,Zhang Z L,et al.Shifting and non-shifting fluorescence emitted by carbon nanodots[J].J Mater Chem,2012,22(13):5917-5920.
[12]Fletcher A N.Quinine sulfate as a fluorescence quantum yield standard[J].Photochem Photobiol,1969,9(5):439-444.
[13]高若梅,刘鸿皋.检出限概念问题讨论-IUPAC及其他检出限定义的综合探讨和实验论证[J].分析化学,1993,(10):1232-1236.
[14]任岗,马红燕,田锐,等.盐酸多西环素与碳量子点相互作用的荧光猝灭效应[J].分析试验室,2016,35(3):305-308.