A new approach for the detection of a nonfluorescent compound by CE‐resonance Raman spectroscopy based on the sweeping‐MEKC mode

Abstract

A CE-resonance Raman spectroscopy (CE-RRS) method based on MEKC and sweeping-MEKC modes is described. A nonfluorescent compound, malachite green (MG), and a doubled Nd:YAG laser (532 nm, 300 mW) were selected as model compound and light source, respectively. In order to carry out a quantitative analysis of MG, a monochromator (effective bandwidth, 0.4 nm) was used to collect the specific Raman line at 1616 cm(-1) (N-phi and C-C stretch, corresponding to 582 nm when the wavelength of the exciting source was 532 nm). As a result, the LOD for MG was 10 ppm, based on the MEKC/RRS mode. This could be improved to 5 ppb when the sweeping-MEKC/RRS mode was applied. Furthermore, with the addition of nano-size silver colloids to the CE buffer the detection limits can be further improved, but the data obtained with surface-enhanced resonance Raman spectroscopy (SERRS) are less useful for quantitative purposes.

Optimization of ultrasound-assisted dispersive solid-phase microextraction based on nanoparticles followed by spectrophotometry for the simultaneous determination of dyes using experimental design

“…Easley absorption of malachite green (MG) (fungicide and antiseptic agent)in aquaculture by fish and subsequent reduction to the lipophilic leucomalachite green (LMG)cause health and environmental hazards [10]. USA, Europe (Council Directive 96/23/EC) and other countriesstrictly hindrance from MG applicationfor veterinary treatment due to its carcinogenic and mutagenic properties [11].Extensive application ofseafoodled to diminish their content in addition to fast growth of the aquaculture industrywhich contain high content of MG as low cost, easy availability may generate hazards for different systems [12,13].AO and MG was quantified by various method and/or instruments likehigh performance liquid chromatography [2,5,10],liquid chromatography [14,15], spectrophotometry [16,17],capillary electrophoresis [18] and electrochemical determinations, [19] Several AO and MGseparation and preconcentrationare carried out based on dispersive liquid-liquid microextraction (DLLME) [16,20], cloud point extraction (CPE) [21,22],liquid-liquid extraction (LLE), solid-phase micro-extraction (SPE) and dispersive solid-phase micro-extraction (DSMPE) [16,[23][24][25][26][27].Most of these reports have their own advantages and disadvantages, while amongst SPE procedures show remarks likesimplicity, capability to eliminate undesirable matrix components which accelerate and candidate this technique for such propose at aforementioned level [14].…”

Recent advances in CE and CEC of pollutants

“…Apart from the many excellent detection modes described above, other novel detection modes, such as chemiluminescence [61] and resonance Raman spectroscopy (RS) hyphenated to CE, were also reported in the recent literature [62,63].…”

Contemporary sample stacking in CE

“…Toward further improvement of the detectability of nonfluorescent compounds, on‐line sample preconcentration by sweeping was applied here with the result of a 3 900 000‐fold increase in sensitivity. Nonfluorescent compounds have also been successfully detected by a CE‐surface‐enhanced resonance Raman spectroscopy method combined with an on‐line sample concentration sweeping‐MEKC mode in two similar papers 112, 113. The LOD for malachite green was 10 ppm without and 5 ppb with sweeping, respectively.…”