The Study On The Detection Methods For Mercury In Blood

At present, the classical analytical methods of mercury in blood are mainly wet digestion and microwave digestion. These methods have the disadvantages of tedious workup, large amounts of thick acid and blood usage and so on. Moreover, because of characteristics of volatilization and adsorption mercury can easily be lost in sample pretreatment, resulting in low recovery rate and inaccurate determination result. A method for determination of mercury in blood using a thiourea mixed extraction method has been put forward in the present paper. Not using the heating the loss of the mercury volatilization can be commendably reduced. Because of stable mercury compounds the absorption loss can be effectively prevented. The method has the advantages of simple operation, high sensitivity, good repeatability and so on.1. A method for determination of mercury in blood using a thiourea mixed extraction method by atomic fluorescence spectrometry has been developed. Using orthogonal test the optimum formula of the thiourea mixed extraction is 0.20% thiourea, 0.10%citric acid, 0.10%EDTA, 0.15% potassium chloride. The detection of limit is 0.06μg/L.The recovery of Hg has been proved to be 95.0%~99.5%. The RSD is less than 5%. The method is suitable for the determination of Hg in blood.2. Extraction time, the concentration of nitric acid, centrifugal time and the volume of hydrogen peroxide are optimized. The experiments show that the appropriate experimental conditions are as follows: optimal time of standing 5 min, concentration of nitric acid 5%, centrifugal time 10min, volume of hydrogen peroxide 50μL.3. The precisions and accuracies of these methods such as wet digestion, microwave digestion, thiourea extraction method, mercaptoethanol extraction method and thiourea mixed extraction method are compared. The stability of the treated samples is discussed. The recovery of these methods such as wet digestion, thiourea extraction method, mercaptoethanol extraction method has been proved to be less than 90%, and the RSD is more than 5%. The recovery of microwave digestion is 91.0%～92.7%. The RSD of microwave digestion is 4.4%～5.0%.The experiment showed that no matter whether precision or accuracy, thiourea mixed extraction method is most highest. The accuracy of thiourea mixed extraction method is 5% higher than the other methods at least. The precision is 0.3% higher than the other methods. Thiourea mixed extraction method overcomes the disadvantages of the classical analytical methods. The mercury content of the sample which is treated by thiourea mixed extraction method keeps invariant for two days,but the blood samples which are treated by wet digestion and microwave digestion must be determined in twenty-four hours.