Silver nanoparticles/poly(L-cysteine) nanocomposite modified pencil graphite for selective electrochemical measurement of guaifenesin in real samples

Abstract

A highly sensitive electrochemical sensor for the determination of guaifenesin (GF) using a modified pencil graphite electrode was developed based on silver nanoparticles/poly(L-cysteine) (AgNPs/PLcys/PGE). The obtained results showed that the electrode response was considerably enhanced during the modification process. The effective surface area of the bare and modified electrodes was determined by using the chronocoulometry method which was accompanied by an enhancement in the effective surface area at each electrode modification step. After optimization, the modified electrode displayed a linear relationship between the concentration of GF and peak current in the range of 3.0 × 10−8 to 3.0 × 10−4 M. The limit of detection was obtained 6.1 × 10−9 M. The sensor was used to measure GF in real samples such as syrup, plasma and urine. The obtained results contained suitable recoveries indicating the precise determination of GF in real samples due to the high selectivity of the sensor.