Novel materials and methods for solid-phase extraction and high-performance liquid chromatography

Abstract

<p>Solid-phase extraction (SPE) is one of the most popular sample preparation techniques for the isolation and preconcentration of organic compounds from aqueous samples. Modified porous polystyrene-divinylbenzene (PS-DVB) resins containing polar groups are superior for SPE of organic solutes from aqueous samples. These modified resins display excellent surface hydrophilicity and improved extraction efficiencies. Silicalite is a hydrophobic molecular sieve with an unusual crystal structure. Because of its unique structure, Silicalite adsorbs organic analytes from aqueous samples due to hydrophobic interactions;The ability of Silicalite and a lightly sulfonated PS-DVB resin to extract various organic test compounds from aqueous samples was compared using identical small cartridges packed with the adsorbents. Both types of resins were incorporated into membranes for more efficient extractions. The percentage recoveries were calculated for the test compounds and used as a measure of SPE efficiency;Heightened awareness of the hazards and pollution caused by the use of organic solvents has led to a search for a more efficient SPE technique. To reduce sample size, elution volume, and time, semi-micro solid-phase extraction (SM-SPE) was developed. The entire SPE process was miniaturized. The apparatus for SM-SPE consisted of a Teflon luer lock syringe as the sample reservoir and fluorocarbon hubbed needles as the extraction columns;Therapeutic drug monitoring usually incorporates high-performance liquid chromatography (HPLC) to separate and quantitate drugs from biological samples. Direct injection of biological samples onto HPLC columns is advantageous in terms of its time and labor saving capabilities. Because of its unique structure and characteristics, Silicalite was employed for the determination of drugs and metabolites in serum and urine using direct injection. Silicalite possesses a hydrophobic interior and hydrophilic exterior. The hydrophilic surface allows passage of small molecules to the hydrophobic interior, while sterically preventing large molecules from entering the pores. Silicalite was able to separate and quantitate various drugs in urine and serum.</p>