In-Tube Solid-Phase Microextraction Coupled to Capillary LC for Carbamate Analysis in Water Samples

Abstract

Recently, the on-line sample preparation technique, intube solid-phase microextraction (SPME), was successfully implemented with a Hewlett-Packard 1100 HPLC system for analysis of carbamates in water samples. This paper describes the coupling of in-tube SPME to capillary LC and explores its utility as a sample preparation method in that format, relative to conventional LC. The Hewlett-Packard HPLC system was upgraded to a capillary LC system using commercially available accessories from LC Packings. The combination of in-tube SPME with a capillary LC system was expected to build on the merits of both in-tube SPME and the capillary LC to generate a sensitive method with an easy, effective, and efficient sample preparation. Due to the relatively large effective injection volume of the in-tube SPME technique (30-45 microL), on-column focusing was employed in order to achieve good chromatographic efficiency. Excellent sensitivity was achieved with very good method precision. For all carbamates studied, the RSD of retention time was between 0.5 and 0.8% under 4 microL/min microgradient conditions. The RSD of peak area counts was between 1.5 and 4.6%. The detection limits for all carbamates studied were less than 0.3 microg/L and, for carbaryl, just 0.02 microg/L (20 ppt). Compared with the conventional in-tube SPME/LC method, the LODs were lowered for carbaryl, propham, methiocarb, promecarb, chlorpropham, and barban, by factors of 24, 45, 42, 81, 62, and 56, respectively. The optimized method was successfully applied to the analysis of carbamates in surface water samples.

Reversed phase liquid chromatography trace analysis of pesticides in soil by on‐column sample pumping large volume injection and UV detection

“…HØrnandØz et al [25] determined trace glyphosate residues in plant material. Gou and Pawliszyn [26] proposed combination of LVI with in-tube solid phase microextraction coupled to capillary LC for carbamate analysis in water samples. Organophosphorus pesticides were determined at trace levels in aqueous samples by direct LVI-HPLC-MS-MS [27].…”

New approach to large‐volume injection in reversed‐phase high performance liquid chromatography: Determination of atrazine and hydroxyatrazine in soil samples

“…The limits of detection and quantitation were estimated to be 0.01 and 0.05 mg/kg, respectively, and recoveries ranged from 80 to 97% with relative standard deviations of 6%. LVI combined with in-tube solid-phase microextraction coupled to capillary LC for carbamate analysis in water samples was proposed by Gou and Pawliszyn [22]. Polar organophosphorus pesticides in aqueous samples were determined at trace levels by direct LVI HPLC-tandem MS [23].…”

Automated sample preparation using in-tube solid-phase microextraction and its application – a review

“…Intube SPME is suitable for automation, and automated sample handling procedures not only shorten the total analysis time but also usually provide better accuracy and precision relative to manual techniques. In-tube SPME technique has been applied to the determination of pesticides, environmental pollutants, drugs, and food contaminants by hyphenation with HPLC, LC-MS, ion chromatography, and capillary electrophoresis (CE) [54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78].…”

“…Actually, a reduction of the extraction efficiency was not observed, even if the Omegawax column was repeatedly used over 500 times [66,69,70]. As a conventional commercial capillary column, Omegawax 250 was used for the extraction of pesticides, drugs, and heterocyclic amines [54,55,56,57,66,69,70,72,76], and Supel-Q PLOT coated with the porous a divinylbenzene polymer was used for the extraction of organometallic compounds, benzodiazepines, and endocrine disruptors [62,63,75,77]. On the other hand, Saito et al used a modified capillary column inserted with stainless steel wire [73] and a polyether ether ketone (PEEK) tube packed with fibrous rigid-rod heterocyclic polymer [61] to increase extraction efficiency.…”

“…The detection limit was below 5 ng mL -1 . Furthermore, Gou et al modified this method using an Agilent autosampler, and applied it to the determination of six carbamates in tap water and surface water samples [55,56,57]. As shown in Fig.…”