Oxidized multiwalled carbon nanotubes for quantitative determination of cationic surfactants in water samples using atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry

Oxidized multiwalled carbon nanotubes (O-MWCNT) are used as preconcentrating probes for the quantitative determination of cationic surfactants (CS+) in water samples using atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry (AP-MALDI-MS). The method is based on the electrostatic interactions of positively charged CS+ with the negatively charged O-MWCNT for the preconcentration and isolation of analytes from sample solutions. The O-MWCNT/AP-MALDI-MS is performed for the determination of CS+ in river- and waste-water samples. The optimum extraction efficiency of CS+ is observed for 7 min of contact time at 1.0 mg dosage of O-MWCNT at pH 7.0. The acceptable relative recovery percentage in water sample is obtained in the range 90.5-97.8% with relative standard deviation (R.S.D.) < 14.5%. The results suggested that the newly proposed method is rapid, accurate and effective and could be successfully applied for the enrichment and quantitative determination of CS+ in water samples.