Photo-degradation of malachite green in mudfish tissues — investigation of UV-induced photo-degradation

Abstract

Ultraviolet (UV) light induced photo-degradation of malachite green (MG) was investigated in the absence of photocatalysts. Photo-degraded intermediates were identified using LC with visible detection and LCelectrospray ionization-MS. Using this analysis, mechanisms for the MG decomposition in aqueous solution and in mudfish tissue were suggested. In aqueous condition, Nde-methylation and the decomposition of the conjugated structures were mainly observed. On the other hand, MG levels in mudfish continuously decreased until they reached a plateau owing to the decomposition of the conjugated structures. These results show that some chemicals in fish tissues could be photo-degraded by UV light without photocatalysts.

UV treatment for degradation of chemical contaminants in food: A review

“…A degradation rate of over 60% was observed when low concentrations of MG, such as 2 and 20 ng mL −1 , were treated with UV 360 at 15 mW cm −2 for 50 min (Lee & Kim, 2012). However lower degradation rates were observed when higher concentrations, such as 200 ng mL −1 , were used (Lee & Kim, 2012). Through further analysis, it was determined that the breakdown of MG causes the formation of five degradation products, and the subsequent UV degradation pathway of the drug in aqueous solutions is illustrated in Figure 9 (Lee & Kim, 2012).…”

“…However lower degradation rates were observed when higher concentrations, such as 200 ng mL −1 , were used (Lee & Kim, 2012). Through further analysis, it was determined that the breakdown of MG causes the formation of five degradation products, and the subsequent UV degradation pathway of the drug in aqueous solutions is illustrated in Figure 9 (Lee & Kim, 2012). Due to these results, the authors were able to further investigate the photodegradation of MG in mudfish (Lee & Kim, 2012).…”

“…Through further analysis, it was determined that the breakdown of MG causes the formation of five degradation products, and the subsequent UV degradation pathway of the drug in aqueous solutions is illustrated in Figure 9 (Lee & Kim, 2012). Due to these results, the authors were able to further investigate the photodegradation of MG in mudfish (Lee & Kim, 2012). During the experiment, mudfish with an initial concentration of 200 ng g −1 MG were prepared, homogenized, and then irradiated by UV 360 at an intensity of 15 mW cm −2 (Lee & Kim, 2012).…”

“…Due to these results, the authors were able to further investigate the photodegradation of MG in mudfish (Lee & Kim, 2012). During the experiment, mudfish with an initial concentration of 200 ng g −1 MG were prepared, homogenized, and then irradiated by UV 360 at an intensity of 15 mW cm −2 (Lee & Kim, 2012). A continuous decrease in MG residues was observed during the first 45 min of treatment, then the degradation rate stabilized once 60% of reduction was achieved, indicating that the degradation of MG is slightly faster in mudfish than in standard solutions (Lee & Kim, 2012).…”

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“…However, residues of malachite green in nature are hazardous compounds that can cause mutagenesis, teratogenesis and chromosomal fractures, leading to serious human health hazards including carcinogenesis, multi-organ tissue injury and developmental abnormalities. 27 Although its manufacture has been banned worldwide, 27,28 MG is still produced and used in some developing countries because of its low price and lack of substitutes. 29 Investigation on biotreatment and detoxification of MG using bio-NPs may provide a new efficient technique to prevent MG-derived health hazards and has attracted increasing attention in recent years.…”