Ultrafast capillary electrophoresis method for the simultaneous determination of ammonium and diphenhydramine in pharmaceutical samples

作者：de Castro Costa Brenda Maria; Marra Mariana Cardoso; Oliveira Thiago da Costa; Abarza Munoz Rodrigo Alejandro; Batista Alex Domingues; do Lago Claudimir Lucio; Richter Eduardo Mathias^*

来源：Journal of Separation Science, 2018, 41(14): 2969-2975.

DOI：10.1002/jssc.201800273

• capillary electrophoresis
• contactless conductivity detection
• pharmaceuticals
• simultaneous analysis

Ammonium and diphenhydramine are active ingredients commonly found in the same pharmaceutical preparations. We report, for the first time, a sub-minute method for the simultaneous determination of ammonium and diphenhydramine. The method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection. Both analytes can be quantified in a single run (approximate to 80 injections/h) using 30mmol/L 2-(N-morpholino)ethanesulfonic acid and 15mmol/L lithium hydroxide (pH6.0) as background electrolyte. The separation by capillary electrophoresis was achieved on a fused-silica capillary (50cm total length, 10cm effective length, and 50m inside diameter). The limits of detection were 0.04 and 0.02mmol/L for ammonium and diphenhydramine, respectively. The proposed method also provided adequate recovery values for spiked samples (100-106 and 97-104% for ammonium and diphenhydramine, respectively). The results obtained with the new capillary electrophoresis method were compared with those of the high-performance liquid chromatography method for diphenhydramine and the Kjeldahl method for ammonium and no statistically significant differences were found (95% confidence level).

• 出版日期2018-7