A fast and simple differential pulse polarographic method was developed for analysis of nicotine in various pharmaceutical formulations (chewing gum, tablets (drops) and patches). This method requires a simple liquid-liquid extraction procedure for chewing gum and patches, or a direct dilution in supporting electrolyte for tablets before polarographic analysis. The polarographic analysis was done in a Britton-Robinson buffer (pH 6.2) as supporting electrolyte. The multimode electrode from Metrohm was used as working electrode (dropping mercury electrode). This method was applied to the determination of the nicotine content in chewing gum, tablets and patches by using the standard addition method. The results are in good agreement with the content declared by the manufacturer. The method is fast, simple and reliable, and it is a complementary method to the chromatographic method being used today for quantitative analysis of nicotine in pharmaceutical formulations. The limit of quantification is assumed to be far below 0.1 mg/l in the polarographic vessel. The method uses simple dilution and/or extraction procedures for sample preparation before polarographic analysis. It is also shown that it is possible to use a glassy carbon electrode with a mercury film (MTFE electrode) for the determination of nicotine in antismoking pharmaceutical products.
Electrochemical detection of quantum dots (QDs) has already been used in numerous applications. However, QDs have not been well characterized using voltammetry, with respect to their characterization and quantification. Therefore, the main aim was to characterize CdTe QDs using cyclic and differential pulse voltammetry. The obtained peaks were identified and the detection limit (3 S/N) was estimated down to 100 fg/mL. Based on the convincing results, a new method for how to study stability and quantify the dots was suggested. Thus, the approach was further utilized for the testing of QDs stability.
- Publication type
- Journal Article MeSH
Novel method for the determination of a tumor marker homovanillic acid (HVA) in human urine was developed. Combination of hollow fiber - based liquid-phase microextraction (HF-LPME) and differential pulse voltammetry (DPV) at a cathodically pre-treated boron doped diamond electrode (BDDE) was applied for these purposes. Optimum conditions were: butyl benzoate as supported liquid membrane (SLM) formed on polypropylene HF, 0.1 mol L-1 HCl as donor phase, 0.1 mol L-1 sodium phosphate buffer of pH 6 as acceptor phase, and 30 min extraction time. HF-LPME-DPV concentration dependence was linear in the range from 1.2 to 100 μmol L-1. Limits of quantification (LOQ) and detection (LOD) were 1.2 and 0.4 μmol L-1, respectively. The applicability of the developed method was verified by analysis of human urine. Standard addition method was used, found HVA concentration was 13.5 ± 1.3 μmol L-1, RSD = 9.3% (n=5).
- MeSH
- Homovanillic Acid MeSH
- Humans MeSH
- Liquid Phase Microextraction * MeSH
- Biomarkers, Tumor * MeSH
- Chromatography, High Pressure Liquid MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
