Glutamate sol-gel amperometric biosensor based on co-immobilised NADP+ and glutamate dehydrogenase

Abstract

In this work the preparation and electrochemical characterisation of a new glutamate amperomet ric sol-gel biosensor is described. A carbon paste electrode was electrochemically modified with the phe nothiazine dye methylene green (MG). The NADP + and glutamate dehydrogenase were co immobilised in a sol⎯gel matrix. When coupled to a flow injection system (FIA) the biosensor showed good electrocatalytic activity towards NADPH oxidation at the potential of + 0.3 V vs. Ag/AgCl; KCl sat., which represents a strong overpotential reduction. The biosensor yielded a linear response from 5.0 × 10 -5 to 1.0 × 10 -2 M glutamate concentration, with a detection limit of 5 × 10 -6 M and reproducibility of results better than 2.3% (RSD). Moreover, the implemented biosensor showed to be still useful after 7 months, 500 determinations.

Amperometric l-glutamate biosensor based on bacterial cell-surface displayed glutamate dehydrogenase

“…In this respect, various methods have been reported with typical linear ranges and LODs (Table 1). Obviously, the Nafion/Gldh-bacteria/PEI-MWNTs/ GCE showed wider dynamic detection ranges and corresponding lower detection limit, in comparison with most purified Gldh based sensors reported so far [40,41,53,54]. The Gldh-bacteria in present work exhibited high activity, specificity and stability, which could be used directly without further labored enzyme extraction and purification, thus greatly improved the stability of the enzyme and sensitivity of the sensor.…”

“…The GLOx based L-glutamate biosensors needs high overpotential and was easily effected by interferents owing to the detection of generated H 2 O 2 [34][35][36][37]. Gldh has been used for the construction of electrochemical glutamate biosensors [38][39][40][41], nevertheless, these sensors experienced either complicated in fabrication, or stability or sensitivity issue, which is probably ascribed to Gldh in part.…”

Highly sensitive determination of l-glutamic acid in pig serum with an enzyme-free molecularly imprinted polymer on a carbon-nanotube modified electrode

“…49 On the one hand, the monomer adopted in this paper contributes the binding sites; 58 on the other hand, MWCNTs improve the detection sensitivity of the sensor. Compared with other MIP electrodes 49 and different modified electrodes, 29,34–36,59–65 this work presents a good linear range and relatively low LOD, and can recognize l -Glu without the aid of enzymes. It can be seen that the enzyme-free sensor developed in this paper has excellent performance.…”