Studies On Determination And Elimination Of Niclosamide Residue In Aquatic Products

Niclosamide (NIC) is a kind of synthetic efficient snail control medicine mainly used for the prevention and control of schistosomiasis, and it is used for to kill wild fish.because of the high toxicity for fish and amphibians. It is administered directly into the aquatic water by splashing and this has led to the increasing acute deaths of aquatic animal, and with highly toxic and carcinogenic properties. Therefore, the danger that NIC can be enriched in the fish and then transmitted through the food chain and finally accumulate to the consumers has gradually aroused the attention of people. As a result, research and testing method of the drug, to study the elimination rule has become particularly important in aquatic products. In this paper, a high performance liquid chromatography tandem mass spectrometric (HPLC-ESI/MS/MS) method for the simultaneous determination of residues of niclosamide and its aquatic products muscles has been established; Acute toxicity and the safe concentration of25%niclosamide ethanolamine salt to channel catfish was investigated; Accumulation and elimination of Niclosamide (NIC) in Ietalurus Punetaus tissue and water at25℃were studied. The results of the study are as follows:1. The high performance liquid chromatography tandem mass spectrometric (HPLC-ESI/MS/MS) method for the determination of Niclosamide(NIC) in aquatic products muscles, which has been set up to the industry standard, was certified by the administration section of agriculture department. Muscle were extracted with ammonic acetonitrile the extracts were blowed by Pressured gas blowing concentrators(N-EVAP) to dryness and then the residues were dissolved in1ml acetonitrile-water, which was purified by C18sorbent. HPLC analyses are performed on the Hypersil Gold C18(100mm×2.1mm×3μm) reversed phase chromatographic column and the temperature of the column at35℃, the Mobile phase is composed of a mixture of solvent acetonitrile and water in a gradient, the flow rate is200μL/min, the injection volume is20.0μL; The tandem mass spectrometry detection is performed in the negative ion mode using heating atmosphere electrospray ion source (HESI) and select reaction monitoring(SRM),and the monitoring mother ion and sub ion were325m/z and289,171m/z, respectively. By the method established in this paper,the recoveries are higher than90%quantitatived by working curve between the added level of0.5μg/kg～20μg/kg. The determination of limits of detection(LED) is about0.2μg/kg and limits of quantification(LOQ) can obtain0.5μg/kg.2. The acute toxicity of Niclosamide to channel catfish (Ietalurus Punetaus) was experimented. Immersion group concentrations were0.605%、0.482%、0.363%、0.242%、0.121mg/L, respectively. The results showed that the concentration of security is0.113mg/L.3Accumulation and elimination of Niclosamide (NIC) in Ietalurus Punetaus tissue and water under the safe concentration test were studied. The concentrations of NIC in water and tissue (muscle,skin) samples were determined by liquid chromatography tandem mass spectrometric (HPLC-ESI/MS/MS). NIC concentration in water decreased quickly on the first day, then, lower than1μg/L and maintained in certain period, but NIC concentration in muscle and skin presented enriched obviously in the first day, and the peak concentrations were45.36±3.53μg/kg and50.95±5.28μg/kg, respectively, then the elimination trends started to level off and maintained a certain concentration fraction in a certain period. The elimination half-life of NIC in muscle and skin were10.66and9.24, respectively, greater than which in water.