Rapid Quantitative Analysis On Biosurfactant Class Metabolites Of Oilfield Produced Fluid

Biosurfactant are produced by the functional microbial metabolism, in produced fluid of oil field, it is of great importance in terms of microbial oil recovery. When cultured microorganisms under certain conditions, the metabolic process will secrete a certain surface active metabolites, such as glycolipids, lipopeptides or neutral lipid derivatives, etc. So far, the quantitative analysis of the surfactant compounds in oilfield produced fluid are still lack a mature method which simple and rapid. And for tracking the microorganisms performance in microbial flooding process, it is the most urgently needed to find a rapid and accurate quantification of biosurfactants. Therefore, in order to obtain a rapid and accurate quantitative method, we made the following experiments.In this thesis two classes of biosurfactant were mainly selected, glycolipid and lipopeptide. By advances and perfects the traditional methods, using the method of oil spreading and phenol sulfuric acid method for rough qualitative and quantitative analysis, combined with high performance liquid chromatography (HPLC) method for precise quantitative, such conclusions have been drawn as folio wings:1、Using the modified phenol-sulfuric acid method, both to meet the needs of rapidly and accuracy of quantitative. Based on the proportion of sample and reagent, Hydrothermal time and temperature were optimized. The result showed that the concentration of rhamnolipid in 100-1000 mg/L range, add 0.5 mL sample and 4.5 mL of reagent in vial, hydrothermal in 80℃ water for 1 h, measuring absorbance, get R2 more than 0.99 standard curve, the quantitative analysis can be used in rapid and easy quantitative.2、The modified oil spread method will answer the purpose of rapid quantitative, but the relative errors are larger. Therefore, optimizing the oil film types, dosage and the add sample dosage, the result showed that:While rhamnolipid are in the 100-500 mg/L concentration, adding 2～4 mL of liquid paraffin and samples 10μL, in this situation, the stability of oil spread are better, the concentration of rhamnolipids had good liner with the diameter of the oil drain ring, which means the standard curve of R2 is above 0.9, and the oil drain ring size changes more obvious form a concentration gradient, the repeatability is higher as well; Within the low concentration range of the 0-100 mg/L,added 1-2 mL of liquid paraffin and samples 50 μ, the stability of oil spread are relatively better, the concentration of rhamnolipids had good liner with the diameter of the oil drain ring, which means the standard curve of R2 is above 0.9. Using the SPSS statistical software to established surfactant concentration and thickness of oil and forecast model relationship between the diameter of the oil drain ring, it shows that the regression model has high precision, each regression coefficient was significant.This predictive model makes the oil drain ring experiment results comparable at different film thickness.Compared with rhamnolipid, the sophorolipid has worse surface activity. In the range of 100-500 mg/L, add 2 mL of liquid paraffin and samples 10 μ, the sophorolipid fitted linear relation basically, which means the standard curve of R2 is above 0.9.Mixed sample volume ratio about 1:1, add 2mL of liquid paraffin and samples 10 uL, compared the two pure samples data above, the the diameter of the oil drain ring of mixed sample are between the the diameter of the oil drain ring of two pure samples, less than rhamnolipid but greater than sophorolipid, the oil drain ring shows a good relation.3-. Direct analysis by high performance liquid chromatography (HPLC), we can obtain a standard curve for accurate quantification. Optimizing the HPLC mobile phase type, proportion of mobile phase, flow rate and solvent, to obtain a relatively mature analysis method and a standard curve of high concentrations of sophorolipid and rhamnolipid.Using HPLC-MS to the quantitative of rhamnolipid,by optimizing the experimental parameters,the detection limit reached 0.1 mg/L,obtained a standard curve by changing the parameters, R2 more than 0.999, can be used for low concentration accurate quantitative.