# Characterization of a simple potentiometric graphite based sensor and its effective applicability in sensitive and selective determination of Cu(II) ion in vegetable foliar, real water and pharmaceutical samples

## TL;DR

A new graphite-based sensor was developed to detect Cu(II) ions in various samples with high sensitivity and selectivity.

## Contribution

The paper introduces a Schiff base-modified graphite sensor with a wide detection range and good reproducibility for Cu(II) determination.

## Key findings

- The sensor showed a linear response to Cu(II) in the range of 1 × 10−7 to 1 × 10−1 mol L−1.
- The detection limit was 5.0 × 10−8 mol L−1 with high selectivity confirmed using multiple methods.
- The sensor successfully detected Cu(II) in water, multivitamin, and vegetable foliar samples comparable to AAS.

## Abstract

The importance of Cu(II) in environmental, biological, and industrial systems makes it crucial to develop a highly selective and sensitive analytical methodology for its determination. Herein, a graphitic based sensor modified with a Schiff base, namely 2-(((3-aminophenyl) imino) methyl) phenol was developed and applied. A broad concentration range (1 × 10−7- 1 × 10−1) mol L−1 was covered by the electrode’s linear response to Cu(II), which had a 29.571 ± 0.8 mV decade−1 Nernstian slope. It was highly reproducible (inter and intraday RSDs%=0.94–2.12), with a response time of approximately 15 s and pH working rang was from 3.5 to 6.5. and had a two-month lifespan. With this modified sensor, 5.0 × 10−8 mol L−1 was the detection limit and1.65 × 10−7 mol L−1 was the limit of quantification. Over a wide range of metal ions, the suggested electrode exhibited very good selectivity for Cu(II) applying separate solution method(SSM), fixed interference method (FIM) and matched potential method (MPM). Cu(II) levels in Several samples like spiked water samples, Hairvogine multivitamin and Nutrifol vegetable foliar were accurately determined potentiometrically by either direct, or standard addition methods using this chemically altered carbon paste electrode giving a comparable results with atomic absorption spectroscopy (AAS) technique. Scanning electron microscope (SEM) combined with energy dispersive X-ray (EDX) were utilized for morphological analysis of sensors’ reactive surface combined with elemental analysis as well.