Evaluation of turbidimetric and nephelometric techniques for analytical determination of N-acetylcysteine and thiamine in pharmaceutical formulations employing a lab-made portable microcontrolled turbidimeter and nephelometer

Abstract

Sequential turbidimetric and nephelometric (STN) analysis for two distinct analytical applications employing a portable microcontrolled turbidimeter and nephelometer (PMTN) is proposed. The PMTN is based on light emitting diodes, photodiodes and, a microcontroller as a central processing unit with a LCD (liquid crystal display) as displayer. The STN methods were applied to determine N-acetylcysteine and two analytical curves in the concentration ranges from 8.0 × 10-5 to 5.0 × 10-3 mol L-1 and from 5.0 × 10-5 to 1.2 × 10-3 mol L -1 were obtained to nephelometry and turbidimetry, respectively. Limits of detection (LOD) of 2.6 × 10-6 and 7.5 × 10 -6 mol L-1 were acquired for these procedures. The STN analyses were also performed to determinate thiamine and two analytical curves in the concentration ranges from 5.0 × 10-6 to 2.5 × 10-4 mol L-1 and from 5.0 × 10-6 to 1.0 × 10-4 mol L-1 with LOD of 5.91 × 10 -8 and 3.11 × 10-8 mol L-1 were acquired for nephelometry and turbidimetry, respectively. © 2011 Sociedade Brasileira de Química.