LAUSR

A fast and sensitive solid phase extraction based on ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry method has been established for determining basic colorant, rhodamine B. This method is based on the extraction of rhodamine B from aqueous solution on surfactant (cetyltrimethylammonium bromide) intercalated montmorillonite (clay k10) followed by elution. The modified material was found to be highly efficient extracting target dyes even at trace levels. The basic methanol solution was used as an eluent for the effective desorption of the dye. The chromatographic separation of analyte was achieved on the Acquity® BEH C18 reversed phase column using a binary mobile phase (a mixture of CH3OH and 0.1% aqueous formic acid solution (75:25, v/v) in isocratic mode at a flow rate of 0.3 mL/min. Both the detection and quantitation of rhodamine B were achieved with a spectrometer of mass operating in positive electrospray ionization mode in less than 1.0 min run time with sharp and excellent peak symmetry. The described method provides excellent quality parameters including linearity (r > 0.998), precisions (day-to-day and run-to-run) (RSD < 3.3%), and sensitivity. Both detection and quantification limits were calculated as signal-to-noise (S/N) ratios of 3 and 10, and were found to be 0.24 and 0.82 ng/mL, respectively. Industrial wastewater samples including the printing press, paper industry, textile industry, processed food industry, and laundry have been analyzed and the quantities of rhodamine B were found to be from 0.45–1.78 μg/mL. The percentage recovery values were obtained in the range of 99%–103% depending on sample matrices.