This work presents a square-wave adsorptive stripping voltammetric sensor for the determination of chloramphenicol (CAP) using a glassy carbon electrode modified with branch-like poly (eriochrome black T) film (P(EBT)/GCE). Branch-like P(EBT) film on the GCE was prepared by electropolymerization using cyclic voltammetry. The morphology of the P(EBT)/GCE was characterized by scanning electron microscopy. The concentration of eriochrome black T monomer and the number of electropolymerization cycles used in the fabrication process were optimized. Operational conditions, such as accumulation potential and accumulation time were also optimized. Sensitive determinations were achieved from controlled adsorption at the P(EBT)/GCE. The P(EBT)/GCE exhibited two linear ranges, 0.01 to 0.10 and 0.10 to 4.0 μmol L−1, with high sensitivity (5.2 μAμM−1). The limit of detection and quantitation were 3 and 11 nmol L−1, respectively. Repeatability (RSD < 2.7%, n = 18), reproducibility (RSD < 2.8%, n = 6) and anti-interference were good. The sensor determined CAP in eye drops and ointment with recoveries between 96 ± 3% and 102 ± 1% (n = 3).

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A novel foam-based colorimetric alcohol sensor was developed for the detection of alcohol in saliva. Detection was based on the color change of a potassium dichromate-sulfuric acid solution absorbed by melamine foam. In the presence of alcohol, the orange colorimetric sensor changed color to brown, green and, ultimately, blue, depending on the concentration of alcohol in the sample. The response of the proposed sensor toward alcohol was linear from 0.10 to 2.5% v/v. The limit of detection was 0.03% v/v. Alcohol concentration could be determined using the naked eye in the range of 0.00 to 10% v/v. The developed alcohol sensor presented good operational accuracy (RSD = 0.30–1.90%, n = 8) and good stability for 21 days when stored at 25 °C and 75 days when stored at 4 °C. The results of alcohol detection with the developed sensor showed no significant difference from the results of spectrophotometric detection at a 95% confidence level (p > 0.05). The sensor was easy to use, small, inexpensive and portable, enabling drivers to accurately measure their own blood alcohol level and providing convenient speed in forensic applications.