Optimization and Application of Liquid Chromatography Determination of Dispersive Liquid-liquid Microextraction Purified Astaxanthin in Shrimp Waste

A new molecularly imprinted solid-phase extraction(MISPE) monolithic cartridge was synthesized, and MISPE-DLLME(DLLME=dispersive liquid-liquid microextraction) was developed for purification of astaxanthin in shrimp waste. The eluent(methanol) from MISPE was used as the dispersive solvent in subsequent DLLME for further purifying and enriching the analyte prior to high-performance liquid chromatography(HPLC) analysis. The mobile phase was methanol-acetonitrile-water-dichloromethane(85:5:5:5, volume ratio), flow rate was 0.7 mL/min and UV wavelength was 476 nm. Under optimal conditions, good linearity was obtained in a range of 0.2―200.0 μg/mL(r²=0.9998) with a limit of detection(LOD) of 0.08 μg/mL, and the extraction recoveries at three spiked levels ranged from 88.3%―92.5% with a relative standard deviation(RSD) less than 4.3%. Moreover, the mean contents of astaxanthin in the three batches of shrimp waste were 95.9, 85.4 and 77.2 μg/g, respectively. This method combining the advantages of MISPE and DLLME results in high selectivity and low cost, which was applied to determining the astaxanthin level in shrimp waste samples.