In-tube solid-phase microextraction with poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary for direct high-performance liquid chromatographic determination of ketamine in urine samples

Abstract

Ketamine was used for anaesthesia originally but has emerged as an abused drug in recent years. The prevalence of ketamine abuse demands a direct and rapid determination method. It is known that in-tube solid phase microextraction (in-tube SPME) can perform extraction with a capillary linked directly to a HPLC system, providing an automated and accurate extraction procedure. In this paper, an in-tube SPME coupled to HPLC method was developed for the determination of ketamine in urine samples with a poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column as the extraction phase, which is expected to provide higher extraction efficiency than open tubular capillaries. After optimizing the extraction conditions, ketamine was extracted directly from urine samples in a wide dynamic linear range of 50-10,000 ng mL(-1), with the detection limit obtained as 6.4 ng mL(-1). The intra-day and inter-day precision for the method was 1.6% and 1.7%, respectively. The urine samples from suspect addicts have been successfully analyzed within 20 min. The re-usability of the monolithic column was also confirmed as no decrease of the extraction efficiency was shown after urine extraction.

Development of in‐tube solid‐phase microextraction coupled to pressure‐assisted CEC and its application to the analysis of propranolol enantiomers in human urine

“…Successful on-line organic polymer monolithic capillary column SPME coupled to HPLC has been reported by our group and applied to the analysis and determination of various compounds in different matrices [28][29][30][31]. Poly(MAA-co-EGDMA) monolithic material was proved to exhibit good extraction of basic compounds because of its hydrophobic polymer bone structure and the acidic pendant groups, and thus was used here for in-tube SPME coupled to capillarybased separation techniques.…”

“…After rinsing with double-distilled water, they were dried at 1607C under N 2 flow for 10 h. Poly(MAA-co-EGDMA) monolithic capillary columns (id 250 mm) were prepared in the same way reported by our group [28][29][30][31][32]. The final length of the monolith in the capillary was controlled by the filling length of prepolymerization mixture consisting of monomer MAA, cross-linker EGDMA, porogenic solvent toluene and dodecanol, and initiator AIBN.…”

Porous polymer monoliths for extraction: Diverse applications and platforms

“…Feng's group have described the use of poly(MAA-co-EDMA) monoliths for sample extraction coupled online with HPLC systems in a number of publications [82][83][84][85][86][87][88]. The offline use of these monoliths has already been described in Section 2.2.…”

Determination of telmisartan in rat tissues by in-tube solid-phase microextraction coupled to high performance liquid chromatography

“…The adsorption of the analyte on the monolithic capillary column was mainly based on hydrophobic interaction, hydrogen bonding and acid -base interaction with the carboxyl pendant groups of the polymer [17]. For intube SPME, it is important to increase the distribution factor of the analyte to obtain rapid and high extraction efficiency.…”

“…As an ideal sample preparation technique, this on-line in-tube SPME technique integrates extraction, concentration, desorption, and injection into a single procedure, and can obtain better accuracy, precision and sensitivity than those of off-line methods. We previously introduced on-line in-tube methods using poly(methacrylic acid-ethylene glycol dimethacrylate, MAA-EGDMA) monolithic material as an extraction medium to determine some basic drugs in plasma [15], serum [16] and urine [17,18] samples. This material was demonstrated to be biocompatible and no additional sample preparation (such as ultracentrifugation and other deproteinization steps) was needed to eliminate the protein component of the sample prior to extraction.…”