Quantitative detection of trace malachite green in aquiculture water samples by extractive electrospray ionization mass spectrometry

Abstract

Exposure to malachite green (MG) may pose great health risks to humans; thus, it is of prime importance to develop fast and robust methods to quantitatively screen the presence of malachite green in water. Herein the application of extractive electrospray ionization mass spectrometry (EESI-MS) has been extended to the trace detection of MG within lake water and aquiculture water, due to the intensive use of MG as a biocide in fisheries. This method has the advantage of obviating offline liquid-liquid extraction or tedious matrix separation prior to the measurement of malachite green in native aqueous medium. The experimental results indicate that the extrapolated detection limit for MG was~3.8 µg·L −1 (S/N = 3) in lake water samples and 0.5 µg·L −1 in ultrapure water under optimized experimental conditions. The signal intensity of MG showed good linearity over the concentration range of 10-1000 µg·L −1 . Measurement of practical water samples fortified with MG at 0.01, 0.1 and 1.0 mg·L −1 gave a good validation of the established calibration curve. The average recoveries and relative standard deviation (RSD) of malachite green in lake water and Carassius carassius fish farm effluent water were 115% (6.64% RSD), 85.4% (9.17% RSD) and 96.0% (7.44% RSD), respectively. Overall, the established EESI-MS/MS method has been demonstrated suitable for sensitive and rapid (<2 min per sample) quantitative detection of malachite green in various aqueous media, indicating its potential for online real-time monitoring of real life samples.

Quantification of twenty pharmacologically active dyes in water samples using UPLC-MS/MS

“…Until now there have been a few published methods for determination of dyes in water samples allowing the detection and quantification of dyes at the concentration level below 1 μg/l. LOQ for MG (0.01 μg/l) in the presented method is lower than LOQ obtained with methods developed by Mitrowska [ 21 ] (0.04 μg/l), Khan [ 12 ] (0.1 μg//l), Zhang [ 7 ] (0.25 μg/l), Fang [ 35 ] (0.5 μg/l) and Ghasemi [ 23 ] (13.6 μg/l). LOQ of another triphenylmethane dye, CV (0.01 μg/l) allows the determination of the dye at lower concentration than LOQ obtained with other authors' methods: Zhang [ 7 ] (0.25 μg/l), Šafařík [ 34 ] (0.5 μg/l), Sadeghi [ 27 ] (4.7 μg/l), An [ 19 ] (16 μg/l), Ghasemi [ 23 ] (17.6 μg/l), Aydin [ 20 ], Yu [ 16 ] (32 μg/l).…”

Constraining the response factors of an extractive electrospray ionization mass spectrometer for near-molecular aerosol speciation

“…Tests with authentic standards show that the EESI-TOF can quantify target inorganic and organic analytes present in complex sample matrices (Fang et al, 2016;Giannoukos et al, 2020;Lopez-Hilfiker et al, 2019;Wu et al, 2013). However, the relative ionization efficiencies (RIEs) of EESI or ESI (where the analyte is directly infused into the ES solution) towards different compounds could vary by orders of magnitude depending on the instrument setting, sample matrices, electrospray solutions, and other experimental conditions (Kruve et al, 2013;Liigand et al, 2018;Kruve et al, 2014;Oss et al, 2010;Mayhew et al, 2020;Lopez-Hilfiker et al, 2019).…”