A new aerosol into-supramolecular solvent microextraction for spectrophotometric determination of crystalline silica in respirable dust using multivariate optimization

摘要

Inhalation exposure to respirable crystalline silica (RCS) strongly affects human health in many industrial environments. There is a need for sensitive and cost-effective methods for the measurement of hazardous RCS in airborne dust. In this study, for the first time, an optimized separation and preconcentration method was developed based on the aerosol into-supramolecular solvent microextraction system for spectrophotometric determination of RCS in workplaces. The proposed method is based on the collection of the RCS on the PVC filter followed by chemical digestion, silicomolybdenum blue complex formation, and subsequent vortex-assisted supramolecular solvent microextraction using solidification of floating drop for spectrophotometric determination. Furthermore, the response surface methodology was utilized to achieve the optimum conditions for the microextraction procedure. Under the optimized conditions, crystalline silica (alpha-quartz) can be determined in the linear range of 10.00-400.00 mu g L-1 (R-2 = 0.9974) with a detection limit (3Sb) of 2.85 mu g L-1 and preconcentration factor of 63. Relative standard deviations were less than 3.4% for intra-day precision and less than 4.7% for inter-day precision. The proposed method was successfully applied for the determination of crystalline silica in airborne sample dust and compared with the NIOSH colorimetric standard method. Also, occupational exposure parameters such as time-weighted average for respirable silica and dust concentrations were calculated.