Development of amperometric biosensor in modified carbon paste with enzymatic preparation based on lactase immobilized on carbon nanotubes
- 28 Downloads
The variety of products derived from milk, without or with lactose, encourages the development of more effective analytical techniques that can be applied to the quality control of both the production line and the final products. Thus, in this work an efficient and minimally invasive method for the detection of lactose was proposed, using a biosensor containing the enzyme lactase (LAC) immobilised on carbon nanotubes (CNTs) that, when reacting with lactose, emit an electrochemical signal. This biosensor was connected to a potentiostat, and its electrochemical cell was composed of the following three electrodes: reference electrode (Ag/AgCl), auxiliary electrode (platinum wire), and working electrode (biosensor) on which graphite (carbon) paste (CP), CNTs, and LAC were deposited. The transmission electron microscopy and scanning electron microscopy were used in the characterisation of the composite morphology, indicating excellent interactions between the CNTs and LAC. The sensitivity of the CP/LAC/CNT biosensor was determined as 5.67 μA cm−2.mmol−1 L and detection limits around 100 × 10−6 mol L−1 (electrode area = 0.12 cm2) and an increase in the stability of the system was observed with the introduction of CNTs because, with about 12 h of use, there was no variation in the signal (current). The results indicate that the association between the CNTs and LAC favoured the electrochemical system.
KeywordsElectrochemistry Nanomaterial Lactosil® Voltammetry Image analysis Biosensor
The authors would like to thank the important financial support of Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil), National Council for Scientific and Technological Development (Bolsas de Produtividade em Pesquisa 302259/2018-0, CNPq, Brazil), Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB, Brazil), the State University of Southwest Bahia (UESB, Itapetinga, Bahia Brazil) and the State University of Santa Cruz (UESC, Ilhéus, Bahia, Brazil) for the equipment and facilities.
- Barberis A, Spissu Y, Fadda A, Azara E, Bazzu G, Marceddu S, Angioni A, Sanna D, Schirra M, Serra PA (2015) Simultaneous amperometric detection of ascorbic acid and antioxidant capacity in orange, blueberry and kiwi juice, by a telemetric system coupled with a fullerene- or nanotubes-modified ascorbate subtractive. Biosens Bioelectron 67:214–223CrossRefGoogle Scholar
- Junior PHR, Oliveira KS, Almeida CER, Oliveira LFC, Stephani R, Pinto MS, Carvalho AF, Perrone IT (2016) FT-Raman and chemometric tools for rapid determination of quality parameters in milk powder: classification of samples for the presence of lactose and fraud detection by addition of maltodextrin. Food Chem 196:584–588CrossRefGoogle Scholar
- Romero-Arcosa M, Garnica-Romob MG, Martínez-Floresc HE (2017) Characterization of Amperometric laccase biosensor based on carbon nanotube. Process Technol 27:279–281Google Scholar