Study On Determination Of Urinary Metabolites Of Toluene, Styrene, N-Hexane By HPLC

Toluene, styrene, n-hexane and other organic compounds are very important chemicals, which are widely used in the field of industry and scientific research. Human may experience the organic solvents stated above in workingplace, which is harmful to the nervous, respiratory, reproductive, digestive, blood, cardiovascular, urinary systems and skin tissues. Therefore, it is very meaningful to monitor and supervise the above harmful substances, which are widely used and easily lead to poision. Following exposure in human, toxic organic compounds are readily transformed into its corresponding metabolites in urine and other biological materials, which could be quantitatively estimated. Such kind of biological monitoring, served as supplement to the air monitoring, provide more accurate and scientific results. However, no mature method has been developed to facilitate simultaneous determination of metabolites of toxic organic compounds in urine of unexposed people. No background information about urine of normal people could be used as references for the establishment of biological monitoring limit, related laws and regulations. As a result, it is quite necessary to develop a method applied to the determination of toxic metabolites in urine of normal people, as a technical support for establishing background information about urine of normal people.A high performance liquid chromatography(HPLC) method was developed for the determination of 2,5-hexanedione(2,5-HD), hippuric acid (HA), mandalic acid (MA), o-cresol in urine. The influence of chromatogram column type, detection wavelength, column temperature, the component and ratio of the mobile phase, flow rate, and so on are discussed. The optimized chromatographic conditions included a Diamonsil C18 column. The detector was Waters 2487 DualλAbsorbance Detector, which was set at the wavelength of 254 nm and 271 nm. For the separation of the analytes, a programmed gradient was applied using methanol, water solution including acids (0.008%H3PO4 and 0.012% CH3COOH, v:v) as the mobile phase. The column temperature was 30℃. The flow rate was 1.0 mL/min. The injection volunm was 7μL. Under the optimized detection conditions, the correlation coefficient of four analytes in the range of 0.9994～0.9997 was obtained. The detection limit was in the range of 0.01-0.5μg/mL. An orthographic experiment was used to optimize the condition of sample pretreatment. The average recovery and relative standard deviations of samples respectively was, HA:91.8%～100.5%,3.2～4.8%; MA:81.6～89.4%,2.1～4.2%; 2,5-HD:86.1～95.1%,4.0～4.4%; o-cresol:84.2～102.7%,4.1～4.6%.Results showed that this HPLC method, which for simultaneous determination of 2,5-hexanedione, hippuric acid, mandalic acid, o-cresol, was sensitive, precise and very adequate for monitoring of urine of unexposed people.