Polyphenol oxidase-based electrochemical biosensors: A review.

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Construction of amperometric biosensor modified with conducting polymer/carbon dots for the analysis of catechol

Tea is a popular beverage all around the world. Tea composition, quality monitoring, and tea identification have all been the subject of extensive research due to concerns about the nutritional value and safety of tea intake. In the last 2 decades, research into tea employing electrochemical biosensing technologies has received a lot of interest. Despite the fact that electrochemical biosensing is not yet the most widely utilized approach for tea analysis, it has emerged as a promising technology due to its high sensitivity, speed, and low cost. Through bibliometric analysis, we give a systematic survey of the literature on electrochemical analysis of tea from 1994 to 2021 in this study. Electrochemical analysis in the study of tea can be split into three distinct stages, according to the bibliometric analysis. After chromatographic separation of materials, electrochemical techniques were initially used only as a detection tool. Many key components of tea, including as tea polyphenols, gallic acid, caffeic acid, and others, have electrochemical activity, and their electrochemical behavior is being investigated. High-performance electrochemical sensors have steadily become a hot research issue as materials science, particularly nanomaterials, and has progressed. This review not only highlights these processes, but also analyzes and contrasts the relevant literature. This evaluation also provides future views in this area based on the bibliometric findings.

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Electrochemical Sensors and Biosensors for the Analysis of Tea Components: A Bibliometric Review

Analytical performance of functional nanostructured biointerfaces for sensing phenolic compounds.

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Nanomaterials as Redox Mediators in Laccase-Based Amperometric Biosensors for Catechol Assay

Carbon paste electrode modified with banana crude tissue CPE‐B, source of Polyphenol Oxidase enzyme for determination of catechol in green tea was developed. The electrochemical properties were assessed using square wave voltammetry in phosphate buffer 0.1 M, pH 7 using standard solutions of catechol. This biosensor exhibits sensitivity 2.32 µA/mg/L and detection limit 0.1 mg/L. Linearity range of the methods was from 1.4 to 15.7 mg/L with correlation coefficient 0.9990. Reproducibility of the signal obtained using 1.4 mg/L solution of catechol resulted with relative standard deviation 3.6% (n = 4). The biosensor was applied for the determination of catechol in green tea samples using two extraction methods: water extraction (s.d. ± 8.3 mg/L) and phosphate buffer solution extraction (s.d. ± 6.8 mg/L). The calculated recovery was between 89% and 92%, proving that the proposed CPE‐B biosensor can be an alternative analytical tool for determination of catechol in tea. PRACTICAL APPLICATIONS: In this study, it is reported the development of a carbon paste electrode modified with banana crude tissue (natural source of PPO enzyme), as alternative methods for determination of catechol in green tea sample using square wave voltammetry technique. In order to improve electroanalytical performance of CPEB, different parameters were optimized such as amount of modifier, pH of working solution, amplitude, frequency, and step potential. The real sample of green tea occasionally is taken in the market.

Determination of catechol in extract of tea using carbon paste electrode modified with banana tissue

Electrochemical determination of atenolol and propranolol using a carbon paste sensor modified with natural ilmenite

Comparative study of the environmental state of Ohrid and Prespa Lakes, Albania.

A modified glassy carbon electrode (Aufilm/GCE) using a gold film was constructed for determination\nof chromium(VI) in real water samples. A GCE was immersed in HAuCl4 solution (10-3 M) and the\nthin layer of gold was electrodeposited for 10 min at −0.4 V (vs. Ag/AgCl). Compared with only GCE,\na strong affinity between chromium and gold species was observed with an increase in Cr(VI) signal.\nThe type of supporting electrolytes, electrodeposition time, scan rate, pH, modulation time and the\nmodulation amplitude were optimized through differential pulse-anodic stripping voltammetry\n(DP-ASV). A calibration graph acquired using the accumulation time of 120 s with a sensitivity of 1.3\n× 10-2 μA/μgL-1 was linear in the range of 10-120 μg L-1. A low detection limit of 5.5 μg/L Cr(VI) and\na strong correlation coefficient R2 = 0.9971 were obtained under the optimal experimental conditions.\nSignals were reproducible and exhibited a relative standard deviation of ±4.5%. A modified sensor\nwas employed to determine the Cr(VI) content in the sewage water samples.

Electrochemical Behaviour of Gold Thin Film GlassyCarbon Electrode for Determination of Chromium(VI)


 Investigation of the quality of drinking water was carried out aiming to evaluate health risks and toxicity arising from the content of heavy metals. Samples were analysed for the content of Pb, Cd, Cr, Ni, Cu, Fe, Zn, Al, and Mn. Water quality and health risk assessment were evaluated by comparing the obtained data with current National, EU, and WHO regulations as well as by using the hazard quotient and cancer risk (HQ and CR). Results showed that Al (in one sample) and Ni (in five samples) exceeded the maximum allowed limits. Based on the metal pollution index, MPI, it was concluded that none of the samples exhibited ‘very good quality’ (MPI > 0.3), whereas the overall quality of Glina bottled water was classified as toxic to humans and Trebeshina as moderately toxic. Selected samples exhibited no evident health risk to humans (HQ < 1). Among the toxic metals analysed, Ni, Cd, and Cr exhibited higher values of cancer risk index (CR > 10−4), whereas Pb exhibited the lowest value. Bottled water such as Qafeshtama, Lajthiza, Tepelena, Dukat, Spring, Living, and Aqua Pana as well as tap water collected in the area of Student's City in Tirana can be considered safe for human consumption.

Loreta Vallja

Papers

Determination of catechol in extract of tea using carbon paste electrode modified with banana tissue

Electrochemical determination of atenolol and propranolol using a carbon paste sensor modified with natural ilmenite

Comparative study of the environmental state of Ohrid and Prespa Lakes, Albania.

Electrochemical Behaviour of Gold Thin Film GlassyCarbon Electrode for Determination of Chromium(VI)

Assessment of health risk induced by heavy metal contents in drinking water