Characterization and application of cetylpyridinium chloride modified clinoptilolite adsorbent for monitoring of sulfasalazine at trace levels in environment and pharmaceutical formulations

In this research, clinoptilolite was modified in situ by using cetylpyridinium chloride and used for solid phase extraction-determination of sulfasalazine. Characteristics of the adsorbent were determined by scanning electron microscopy, X-ray diffraction spectroscopy, thermogravimetric analysis, EDX-mapping and Fourier transform-infrared spectroscopy. The prepared adsorbent is able to interact through non-polar and ionic interactions, due to having cetylpyridinium moieties. Cetylpyridinium chloride concentration, pH, amount of clinoptilolite, extraction time, composition and volume of the eluent, elution time and ionic strength as the affecting parameters were evaluated, and the best conditions were selected to achieve the maximum sensitivity for the spectrophotometric determination of sulfasalazine at 450 nm. Under the optimum conditions, linear range and limit of detection for sulfasalazine were 0.02-5 µmol L-1 and 4 nmol L-1, respectively. Sulfasalazine in different pharmaceutical formulations was determined by the method, successfully. As well, various soil and environmental water samples were analyzed to evaluate the applicability of the established method.