Desenvolvimento e aplicação de sensor biomimético descartável para detecção seletiva de hidroquinona
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Data
2011-08-18
Autores
Boni, Thayz Cristina [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Este trabalho descreve o desenvolvimento e aplicação de um sensor biomimético descartável com transdução amperométrica, sensível a hidroquinona (HQ). Para isto, eletrodos impressos de grafite – SPE (FS-1, Florence sensors®) foram modificados com um catalisador biomimético do sítio ativo da tirosinase, uma cupro-enzima. O complexo de cobre usado foi o cloreto de tris-2,2’-bipiridil cobre II, [Cu(dipy)3]Cl2. Para efeitos de comparação também foram preparados sensores empregando eletrodos de carbono vítreo convencionais (GC). Os sensores foram preparados modificando os eletrodos SPE e GC com membrana de Nafion® dopada com o complexo de cobre. Para tal, foram misturados em aparelho de ultrassom, 100 μL de uma solução de complexo 5 mg mL-1, preparada em dimetilformamida (DMF) com 50 μL de solução de Nafion® a 5 % (v/v). A seguir, 100 μL da mistura foram colocados na superfície do GC e 10 μL sobre o SPE. A resposta do sensor à base de SPE (sensor- SPE) foi otimizada usando amperometria. Obtendo-se as melhores respostas em tampão Pipes 0,01 mol L-1 contendo 60 μmol L-1 de H2O2 e aplicando potencial de -300 mV vs Ag/AgCl. Sob estas condições o sensor-SPE mostrou uma faixa de resposta entre 6,0 x 10-5 e 5,6 x 10-4 mol L-1, sensibilidade de 5593,6 μA L mol-1, limite de detecção e quantificação de 5,4 x 10-6 e 1,80 x 10-5 mol L-1, respectivamente. Tratando-se de um sensor biomimético seu comportamento hiperbólico foi confirmado, e a constante aparente de Michaellis-Menten foi calculada através do gráfico de duplo recíproco obtendose um valor de 5,6 x 10-5 mol L-1, indicando uma alta afinidade do complexo pela HQ. Estudos voltamétricos também foram realizados visando à caracterização eletroquímica do sistema proposto. A seletividade do sensor foi estudada em vários compostos fenólicos...
This paper describes the development and application of a biomimetic sensor disposable with amperometric transduction, sensitive to hydroquinone (HQ). For this, printed graphite electrodes - SPE (FS-1, Florence sensors®) were modified with a biomimetic catalyst of the active site of tyrosinase, a cupro-enzyme. The copper complex used was the tris–2,2'-bipyridil cooper (II) chloride, [Cu(dipy)3]Cl2. For comparison were also prepared sensors employing conventional glassy carbon electrodes (GCE). The sensors were prepared by modifying the SPE and GCE electrodes with Nafion® membrane doped with the copper complex. For this, were mixed in an ultrasonic apparatus, 100 μL of 5 mg mL-1 complex solution, prepared in dimethylformamide (DMF), with 50 μL of Nafion® 5% (v/v) solution. Then 100 μL of this mixture were placed on the surface of GCE and 10 μL on the SPE. The response of the SPE-based sensor (sensor-SPE) was optimized using amperometry. Obtaining the best responses in 0.01 mol L-1 Pipes buffer containing 60 μmol L-1 H2O2 and applying potential of -300 mV vs Ag/AgCl. Under these conditions the SPE-sensor showed a response range between 6.0 x 10-5 and 5.6 x 10-4 mol L-1, sensitivity of 5593.6 μA L mol-1, limit of detection and quantification of 5.4 x 10-6 and 1.80 x 10-5 mol L-1, respectively. In this case, the hyperbolic behavior of the sensor response was confirmed, and the Michaelis-Menten apparent constant was calculated by the Lineweaver-Burk graph, obtained a value of 5.6 x 10-5 mol L-1, indicating a high affinity of the complex for the HQ. Voltammetric studies were also conducted to the electrochemical characterization of the proposed system. The selectivity of the sensor was studied in some phenolic compounds and the reproducibility in the sensors construction was evaluated as the relative standard deviation... (Complete abstract click electronic access below)
This paper describes the development and application of a biomimetic sensor disposable with amperometric transduction, sensitive to hydroquinone (HQ). For this, printed graphite electrodes - SPE (FS-1, Florence sensors®) were modified with a biomimetic catalyst of the active site of tyrosinase, a cupro-enzyme. The copper complex used was the tris–2,2'-bipyridil cooper (II) chloride, [Cu(dipy)3]Cl2. For comparison were also prepared sensors employing conventional glassy carbon electrodes (GCE). The sensors were prepared by modifying the SPE and GCE electrodes with Nafion® membrane doped with the copper complex. For this, were mixed in an ultrasonic apparatus, 100 μL of 5 mg mL-1 complex solution, prepared in dimethylformamide (DMF), with 50 μL of Nafion® 5% (v/v) solution. Then 100 μL of this mixture were placed on the surface of GCE and 10 μL on the SPE. The response of the SPE-based sensor (sensor-SPE) was optimized using amperometry. Obtaining the best responses in 0.01 mol L-1 Pipes buffer containing 60 μmol L-1 H2O2 and applying potential of -300 mV vs Ag/AgCl. Under these conditions the SPE-sensor showed a response range between 6.0 x 10-5 and 5.6 x 10-4 mol L-1, sensitivity of 5593.6 μA L mol-1, limit of detection and quantification of 5.4 x 10-6 and 1.80 x 10-5 mol L-1, respectively. In this case, the hyperbolic behavior of the sensor response was confirmed, and the Michaelis-Menten apparent constant was calculated by the Lineweaver-Burk graph, obtained a value of 5.6 x 10-5 mol L-1, indicating a high affinity of the complex for the HQ. Voltammetric studies were also conducted to the electrochemical characterization of the proposed system. The selectivity of the sensor was studied in some phenolic compounds and the reproducibility in the sensors construction was evaluated as the relative standard deviation... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Quimica analitica, Hidroquinonas, Biossensores, Analytical chemistry, Hydroquinones, Biosensors
Como citar
BONI, Thayz Cristina. Desenvolvimento e aplicação de sensor biomimético descartável para detecção seletiva de hidroquinona. 2011. 98 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Química, 2011.