Functionalized‐multiwalled carbon nanotubes as a preconcentrating probe for rapid monitoring of cationic dyestuffs in environmental water using AP‐MALDI/MS

Abstract

A simple and sensitive method was developed for the rapid analysis of cationic dyestuffs from river and industrial wastewater using functionalized-multiwalled carbon nanotubes (f-MWCNT) with atmospheric pressure-matrix assisted laser desorption/ionization mass spectrometry (AP-MALDI/MS). The separation and preconcentration of analytes from sample solution was based on electrostatic force of attraction between positive dyestuffs and negatively charged f-MWCNT. The optimum enrichment of the three dyestuffs was observed at pH 5.0 for 3 min contact time and using 1 mg f-MWCNT in 1 mL water sample. The developed method has been successfully applied for the determination of three cationic dyestuffs namely neutral red (NR), brilliant cresyl blue (BB), and methylene blue (MB) in real world samples including river and industrial wastewater. The relative recoveries of dyestuffs from water sample were in the range 88.6-98.4%, indicating that the matrix had little effect on enrichment of analytes. The LOD and LOQ for cationic dyestuffs in water were 0.5-1.9 and 1.6-6.0 microg/L, respectively. All the results indicated that the proposed method could be used for the simultaneous determination of the three cationic dyestuffs in river and industrial wastewater at trace levels without the need of any chromatographic separation techniques.

Modified Multiwalled Carbon Nanotubes for Treatment of Some Organic Dyes in Wastewater

“…At higher pH values, the cations dyes are easily attached on the surface of negatively charged functionalized CNTs through electrostatic force attractions [26]. The removal % of basic orange dye increases from 55, 47, 37.7, and 32.6 to 74, 70, 66.3, and 65.7 for dye concentration 5, 10, 20, and 30 ppm, respectively, with the increase in pH from 3 to 8.5, while the removal % of methyl violet dye increases from 16.83 to 50 for dye concentration of 30 ppm with the increase in pH from 3 to 8.5.…”

Recent progress in application of carbon nanomaterials in laser desorption/ionization mass spectrometry

“…Oxidized CNTs To improve the dispersibility of CNTs in solution and on the MALDI target, CNTs can be chemically oxidized to introduce polar groups at the surface [41][42][43][44][45][46]. Ren et al [47] developed oxidized CNTs as a MALDI matrix.…”

Matrix-assisted laser desorption/ionization mass spectrometry for quantitative determination of β-blocker drugs in one-drop of human serum sample

“…Recently, MALDI-MS has been applied for the monitoring of drugs and environmental toxicants due to its high sample throughput and easy operations [17][18][19][20]. The proposed method is rapid and cost effective for analysis of ␤-blocker drugs in serum samples.…”

“…Sample preparation in MALDI-MS is the most important step for obtaining a good quality spectrum, which could be helpful for easy identification of particular target compounds in complex samples. Several sample preparation methods are regularly practiced for the MALDI-MS analysis of drugs, proteins, and pollutants from complex matrices samples [13][14][15][16][17][18][19][20]. The most widely used techniques for the separation and preconcentration of trace amount of analytes include, liquid-liquid extraction (LLE) [21] and solid-phase extraction (SPE) [22].…”