A sensitive square‐wave voltammetry method was developed to determine cholecalciferol (vitamin D₃) in pharmaceutical products at boron‐doped diamond electrode as a working electrode. Vitamin D₃ provided a well‐defined voltammetric peak at around +1.00 V (vs. Ag/AgCl, 3.5 mol dm⁻³) in 0.02 mol dm⁻³ Britton‐Robinson buffer pH 5.0 prepared in 50 % ethanol. The influence of various factors such as type and pH of the supporting electrolyte, scan rate and square‐wave parameters were studied and optimized. Under optimum conditions, the oxidation peak current increased linearly with the concentration of vitamin D₃ over the range of 2 to 200 μmol dm⁻³. The calculated limit of detection and limit of quantitation were 0.17 μmol dm⁻³ and 0.51 μmol dm⁻³, respectively. The boron‐doped diamond electrode exhibited specific recognition capability for cholecalciferol amongst possible interferences, and the determination of vitamin D₃ was possible in samples such as commercial pharmaceutical products without complicated sample pretreatments.

中文翻译：

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硼掺杂金刚石电极电化学测定药品中的维生素D3。

开发了一种灵敏的方波伏安法，用于测定掺硼金刚石电极作为工作电极时药品中的胆钙化固醇（维生素D ₃）。在50％乙醇中配制的0.02 mol dm ^-3 Britton-Robinson缓冲液pH 5.0中，维生素D ₃在+1.00 V左右提供了一个明确的伏安峰（相对于Ag / AgCl，3.5 mol dm ^-3）。研究并优化了各种因素的影响，例如支持电解质的类型和pH，扫描速率和方波参数。在最佳条件下，氧化峰电流随维生素D ₃的浓度在2至200μmoldm ^-3的范围内线性增加。计算的检测极限和定量极限分别为0.17μmoldm ^-3和0.51μmoldm ^-3。硼掺杂的金刚石电极在可能的干扰物中表现出对胆钙化固醇的特异性识别能力，并且无需复杂的样品前处理即可在样品（如商业药品）中测定维生素D ₃。