Preparation Of Monolithic Sorbents And Their Pretreatment Properties For Blood Samples

Traditional Chinese medicine is the treasure of Chinese traditional medical culture,which has various active components and pharmacological activities.Quantitative analysis on one or several main active components in blood is of great significance to the rational use of traditional Chinese medicine and the study of drug safety.Blood sample is one of the most common biological samples,which has the characteristics of complex components and large differences in content between components.Therefore,pretreatment is often required before analysis.Solid-phase extraction（SPE）is one of the most commonly used methods for blood samples pretreatment,wherein SPE sorbent is the key element affecting the extraction effect.Porous polymer materials have shown excellent properties of adsorption and chromatography in complex sample-pretreatment,due to their advantages of good permeability,easy modification and strong reusability.In this work,two kinds of functional monolithic SPE sorbents were prepared according to the structures and properties of different saponins in traditional Chinese medicine.Combining with high-performance liquid chromatography（HPLC）,an on-line SPE-HPLC method was used to extract and detect active traditional Chinese medicine components from blood.The phenyl-based polymer monolithic SPE column was prepared via in-situ radical polymerization using ethylene glycol phenyl ether acrylate as the monomer,ethylene glycol dimethacrylate and trimethylolpropane triacrylate as crosslinkers,ethylene glycol,1-dodecanol and N,N-dimethylformamide as tri-porogens,azobisisobutyronitrile as the initiator,which aimed at the structure and properties of dioscin.The prepared sorbents were characterized by scanning electron microscopy（SEM）,nitrogen adsorption-desorption method and mercury intrusion method.In combination with HPLC system,the blood matrix was removed by on-line SPE-HPLC method and the content of dioscin was determined simultaneously.The results show that the spiked recoveries of the method are in the range of96.61%¹13.73%,the limit of detection and limit of quantification of dioscin is 3.4 ng mL^-1and 10.0 ng mL^-1,respectively.Aiming at the structure and properties of polyphyllins,a cyclohexyl-based monolithic SPE column was prepared using cyclohexyl methacrylate as the monomer,ethylene glycol dimethacrylate as the crosslinker,isopropyl alcohol and 1-dodecanol as porogens,as well as benzoyl peroxide and N,N-dimethyl aniline as initiators.The internal morphology and pore structure were characterized by SEM and nitrogen adsorption-desorption.In combination with HPLC system,four kinds of polyphyllins in mouse blood were detected by online SPE-HPLC method.The results show that the spiked recoveries of the method are in the range of 92.59%¹05.15%,the limits of detection are lower than 4.8 ng mL^-1,and the lower limits of quantification are the same as 10.0 ng mL^-1.The homemade SPE columns show advantages of low back pressure,good permeability and strong reusability.The on-line combination of sample pretreatment and quantitative analysis with HPLC system is simple and efficient,which can not only avoid the interference caused by protein matrix in blood,but also protect the analytical column and detector.