Application Of Online Solid Phase Extraction Technology In Food Analysis

Modern analytical chemistry require analytical methods of lower and lower detection limit,the matrix of samples is more and more complex and requirements of analytical flux is becoming higher and higher.These requirements promote the sample pretreatment technique to develop continuously.Compared with traditional pretreatment methods,The technique of on-line solid phase extraction has several advantages,for example,the extraction columns can be reused,amount of consumed solvent is smaller,analytical process can be fully automatic and avoid manual operation error.In recent years,the technique of on-line solid phase extraction has been developed well and been widely used in various fields depended on its own merits.In this study,applying the technique of on-line solid phase extraction,novel analytical methods have been developed to detect the synthetic colorants in beverage,the parabens in carbonated drinks and benzo(a)pyrene in vegetable oil and grains respectively.The main contents in this study are as follows:1.A rapid method was developed for the simultaneous determination of the synthetic colorants in beverage by the technique of on-line solid phase extraction coupled with high performance liquid chromatography.The detected analytes contain amaranth,carmine,sunset yellow,allura red and erioglaucine.The effect of the kinds of on-line solid phase extraction column,mobile phase,velocity of flow,washing solution and washing time on purification were researched.The effect of the kinds of analytical column,time of valve switching,column temperature and velocity of flow on separation was researched.The detections were performed on ultraviolet(UV)detection with the best detection wavelength.External standard method was used for quantification.The result showed that the calibration curve of the 5 synthetic colorants gained good linearity and all the correlation coefficients(r2)were more than 0.9999.The limit of detection(LODs)were 0.02 mg/kg?0.08 mg/kg and the limit of quantification(LOQs)were 0.08 mg/kg?0.44 mg/kg.The recovers of the 5 synthetic colorants is the spiked samples of three levels(low,medium and high level)were in the range of 94.5%?103.0%.The relative standard deviation(RSDs,n=6)were in the range of 0.4%?2.7%.This method was sample,rapid,reproducible and suitable for qualitative and quantitative analysis of the synthetic colorants in beverage.This method can be used for routine detection.2 A rapid method was developed for determination of the parabens in carbonated drinks by the technique of on-line solid phase extraction coupled with high performance liquid chromatography.The effect of the kinds of on-line solid phase extraction column,washing solution,washing time,elution solution and elution time on purification were researched.The effect of the kinds of analytical column,analytical mobile phase,column temperature and velocity of flow on separation was researched.The detections were performed on ultraviolet(UV)detection with the best detection wavelength.External standard method was used for quantification.The result showed that the calibration curve of the 2 parabens in carbonated drinks gained good linearity and all the correlation coefficients(r2)were more than 0.9999.The limit of detection(LODs)were 0.10 mg/kg and 0.20 mg/kg,respectively.The limit of quantification(LOQs)were 0.25 mg/kg and 0.60 mg/kg,respectively.The recovers of the 2 parabens is the spiked samples of three levels(low,medium and high level)were in the range of 95.9%?105.2%.The relative standard deviation(RSDs,n=6)were in the range of 1.6%?5.7%.This method was sample,rapid,reproducible and suitable for the simultaneous determination of the parabens in carbonated drinks.This method can be used for routine detection.3.A rapid method was developed for the determination of the benzo(a)pyrene in vegetable oil and grains by the technique of on-line solid phase extraction coupled with high performance liquid chromatography.The effect of extraction solvent and Ultrasound extraction conditions on the extraction efficacy of benzo(a)pyrene were researched.The effect of the kinds of on-line solid phase extraction column,mobile phase,velocity of flow and sample injection time on purification were researched.In addition,the effect of elution solution,elution time,the kinds of analytical column and analytical mobile phase on separation was researched.The detections were performed on fluorescence detection(FLD)with the best detection wavelength.External standard method was used for quantification.The result showed that the calibration curve of the benzo(a)pyrene gained good linearity and the correlation coefficients(r2)was more than 0.9999.The limit of detection(LOD)was 0.15 ?g/kg and the limit of quantification(LOQ)was 0.45 ?g/kg.The recovers of the benzo(a)pyrene in the spiked samples of three levels(low,medium and high level)were in the range of 95.60%?103.1%.The relative standard deviation(RSDs,n=6)were in the range of 1.2%?3.8%.This method was sample,rapid,reproducible and suitable for qualitative and quantitative analysis of the benzo(a)pyrene in vegetable oil and grains.This method can be used for routine detection.