Estudio del zinc en plasma seminal mediante métodos colorimétricos

Abstract

ObjectivesThe aim of the current study is to evaluate the possible use of two commercial kits for the colorimetric determination of zinc in human seminal plasma as an alternative to the complex analytical methodology of atomic absorption spectrophotometry and to assess the relation between zinc and citrate in seminal plasma. PatientsThe study included 160 patients, aged 17 to 63 years, who came to the Andrology service proceeding fundamentally from the Sterility, Urology, Endocrinology and Oncology Departments. MethodsThe study included the comparison of the method of reference for the determination of zinc in seminal plasma, atomic absorption spectrophotometry and the colorimetric methods, the validation of both colorimetric methods (based on the chomophores 5-Br-PAPS and Nitro-PAPS, respectively) determining imprecision, linearity and limit of quantification and the correlation study between zinc and citrate. ResultsBoth colorimetric methods and atomic absorption spectrophotometry are interchangeable.The average within-run variation (%CV) is 2.42% with the 5-Br-PAPS based kit and 5.81% with the Nitro-PAPS based kit.In the linearity study, both methods present a determination coefficient of 0.999 at zinc concentrations between 10–500μg/dl. However the percentages of recovery in that range are better with the 5-Br-PAPS based kit.A significant positive correlation was observed between zinc and citrate (r=0.724, P<0.001). ConclusionColorimetric methods are a good alternative to atomic absorption spectrophotometry, the colorimetric method based in 5-Br-PAPS showing better performance.