| Solid phase extraction and flow injection spectrophotometry (FIA) method was developed to analyze the cholesterol content in oil. Cholesterol and o-phenylenediamine formed polymer with concentrated sulfuric acid, which had maximum absorption peak at 413 nm, so the FIA automatic analysis method was established for quantitative analysis of cholesterol. When the linearity of this method ranged from 2.0 mg/L to 100 mg/L,the mass concentration of cholesterol had good linear relationship with the height of peak. The correlation coefficient was 0.999 2, the relative standard deviation was 1.81% (20 mg/L of cholesterol, n=12) and the limit of detection was 0.16 mg/L.The results showed that the solid phase extraction and FIA method had items of simpleness, rapidness, accuracy and few reagents consumption, and the cholesterol content in oil could be determined within 30 min. The instrument was compact and portable,which was suitable for on-site inspection of cholesterol content in oil and rapid identification of swill-cooked dirty oil. |
