Study On Evaluation And Environmental Application Of Solid-phase Extraction Materials

Solid-phase extraction (SPE) is nowadays the most appropriate method for enrichment of target compounds in complex samples. As a main sample preparation method, SPE technology is increasingly used in the field of environment, food, biological and so on. However, because of difference selective interaction mechanism of SPE sorbents based on the different physico-chemical properties, most of the available SPE cartridges exhibit different recoveries. It is important to research the properties of SPE bonded silica gel materials and build a evaluation system for them. In this paper, SPE materials have been evaluated extensively. The main researches and conclusions are as follows.1. The elemental analysis of SPE materials (including C, H, N, etc.), as well as the test of pore size, surface area and pore volume were carried out in this study. The results showed that the carbon content of most of studied SPE materials were higher than 15%. High carbon content can increase the absorption capacity effectively. BET test data provided information that after bonding alkyl C18, the surface area of silicone materials was decreased apparently, and the average pore size of the majority were 6~10 nm. Compared to the HPLC packing materials, SPE materials have large surface area, high carbon content and small average pore size.2. Chromatographic properties of SPE materials have been investigated in reversed phase mode in the separation of test mixture of butylbenzene, pentylbenzene, triphenylene, o-terphenyl, caffeine, benzylamine and phenol. The hydrophobicity, steric selectivity, silanol group capacity and ion exchange capacity have been compared with a wide range of SPE materials. The carbon content is the main factors in deciding the hydrophobicity and steric selectivity. The amount of alkyl and hydrophobicity is very close between the different brands of SPE materials.3. The absorption capacity and recovery have been studied for much brands of reversed phases SPE C18 columns. Phenol was used as probe. The results showed that most of the columns exhibited similar performance in the determination of phenol in environmental water samples. But one brand of SPE C18 column can not retain phenol. And further study showed that silanol group capacity is the most critical chemical indicators in deciding the absorption of phenol.