On-Line Determination Of Emergency Pollution Of Citrinin In Drinking Water By Flow Injection Chemiluminescence And Emergency Warning

Frequent drinking water pollution incidents not only affect the security of people’s life and property but also have a negative impact on social stability and development, so it is necessary to establish an effective on-line monitoring technology and emergency response mechanism for the sudden toxic pollution in drinking water.The aim of this thesis is to build an on-line monitoring method to detect citrinin, a potential sudden polluted hazard in drinking water, by luminol-potassium ferricyanide flow-injection chemiluminescence method. The study covers:(1) Relationship between citrinin and fundamental characteristics of drinking water;(2) Optimal testing conditions of flow-injection chemiluminescence method for citrinin;(3) Extraction of citrinin from red yeast rice;(4) Potential hazardous of citrinin;(5) Removal of citrinin from drinking water.The results obtained are as follows:1. Water p H declined significantly while the refractive index increased linearly in the range of 1~50 mg/L of citrinin and conductivity increased significantly in the range of 0.1~10 mg/L of citrinin, indicating that these properties can be used as indicators for monitoring and alerting the emergency contamination of drinking water.2. Citrinin can enhance the chemiluminescence reaction of potassium ferricyanide and luminol in sodium hydroxide medium. The optimal conditions are as follows: the concentration of luminol was 6×10-4 mol/L, the p H of luminol was 13.6, and the concentration of potassium ferricyanide was 6×10-4 mol/L. The linear range for citrinin detection was(5×10-3 mg/L~1.0×10-1 mg/L),(1.0×10-1 mg/L~1.0 mg/L) under the optimal experimental conditions. The detection limits was 4.92×10-5 mg/L and the relative standard deviation(RSD) for the determination was 6.89%(n=11).3. Red yeast rice was chosen as the raw material in this experiment. By using acidized methanol(methanol: 20%H2SO4=4:1,v/v) as an extractant, the optimal conditions are as follows: ultrasound temperature 40℃, ultrasound time 25 min, and ultrasound frequency 55 KHz.4. Eighteen different brands of red yeast rice were sampled to test citrinin. Results showd that all of these samples contained citrinin except for one sample, and the content of citrinin in these red yeast rice were from 1.16 to 59.59 mg/Kg. The maximum content of citrinin from monascus rice which was fermented by the commercially available red yeast rice was 1.62 mg/L when cultivated to 11 d. Citrinin was stable in incandescent light and dark in drinking water.5. Hydrogen peroxide, ultraviolent rays, ozone and heat treatment can reduce the content of citrinin in drinking water. Activated carbon can also remove citrinin, but the effect is various with its particle size. Powder activated carbon showed better effect on removal of citrinin than granular activated carbon in drinking water. The obtained optimal technique parameters for removal of citrinin in drinking water by powder activated carbon were 0.8 g/L treated within 5 min, resulting in the removal effects of 109.86%(theoretical value).