Membrane extraction with a sorbent interface (MESI) is a sample preparation technique with a rugged and simple design allowing for solvent-free, on-line performance. When coupled to gas chromatography (GC), MESI is an extremely promising tool for the analysis of volatile organic compounds (VOCs), as it is selective and sensitive for detecting trace levels of analytes. A new calibration method to be used with the MESI technique is presented herein. The aim of this project was to characterize and quantify the biomarker ethylene in human breath and plant emissions. The MESI-GC system was optimized, and an external calibration curve for ethylene standard was obtained. Qualitative measures were obtained from emissions of the higher plant Arabidopsis thaliana. The dominant calibration method was validated by examining changes in mass transfer trends when flow and temperature conditions were altered. Finally, the dominant calibration method was used to quantify ethylene in real human breath samples from non-smoking and smoking volunteers. Results were consistent with those reported in literature. These findings suggest that the dominant calibration technique is a useful tool for monitoring ethylene in human breath and Arabidopsis.

Membrane extraction with a sorbent interface (MESI) is a sample preparation technique with a rugged and simple design allowing for solvent-free, on-line performance. When coupled to gas chromatography (GC), MESI is an extremely promising tool for the analysis of volatile organic compounds (VOCs), as it is selective and sensitive for detecting trace levels of analytes. A new calibration method to be used with the MESI technique is presented herein. The aim of this project was to characterize and quantify the biomarker ethylene in human breath and plant emissions. The MESI-GC system was optimized, and an external calibration curve for ethylene standard was obtained. Qualitative measures were obtained from emissions of the higher plant Arabidopsis thaliana. The dominant calibration method was validated by examining changes in mass transfer trends when flow and temperature conditions were altered. Finally, the dominant calibration method was used to quantify ethylene in real human breath samples from non-smoking and smoking volunteers. Results were consistent with those reported in literature. These findings suggest that the dominant calibration technique is a useful tool for monitoring ethylene in human breath and Arabidopsis.

Solid phase microextraction (SPME), needle trap device (NTD), and membrane extraction with a sorbent interface (MESI) are solvent-free sample preparation techniques that were developed to perform the rapid routine analysis of organic compounds (VOCs) in various environmental matrices by integrating sampling, extraction, preconcentration and sample introduction procedures into one step. A portable ion mobility spectrometry (IMS) analyzer has some advantages, such as small size, light weight, operability under ambient pressure, air as carrier gas, and sensitivity, all of which make IMS suitable for on-site monitoring for low concentration of analytes. The aforementioned sampling and preconcentration techniques were coupled with a portable IMS analyzer, as well as a thermal desorption unit that can accommodate SPME, NTD and MESI, which was modified and combined with IMS for on-site monitoring of volatile organic compounds (VOCs) from human breath and plant emissions. Experimental results demonstrated that low detection limits were achievable for gaseous analytes, (25 ng/L for acetone (SPME-IMS), 43 ng/mL (NTD-IMS) and 2.3 ng/mL (MESI-IMS) for α-pinene). These three analytical systems were applied for on-site rapid determination of acetone in human breath and α-pinene from plant emissions respectively. The salient features of these systems that make them suitable for on-site monitoring of volatile organic compounds in different sources are: small size, simple operation, fast and/or on-line sampling, rapid analysis.

Solid phase microextraction (SPME), needle trap device (NTD), and membrane extraction with a sorbent interface (MESI) are solvent-free sample preparation techniques that were developed to perform the rapid routine analysis of organic compounds (VOCs) in various environmental matrices by integrating sampling, extraction, preconcentration and sample introduction procedures into one step. A portable ion mobility spectrometry (IMS) analyzer has some advantages, such as small size, light weight, operability under ambient pressure, air as carrier gas, and sensitivity, all of which make IMS suitable for on-site monitoring for low concentration of analytes. The aforementioned sampling and preconcentration techniques were coupled with a portable IMS analyzer, as well as a thermal desorption unit that can accommodate SPME, NTD and MESI, which was modified and combined with IMS for on-site monitoring of volatile organic compounds (VOCs) from human breath and plant emissions. Experimental results demonstrated that low detection limits were achievable for gaseous analytes, (25 ng/L for acetone (SPME-IMS), 43 ng/mL (NTD-IMS) and 2.3 ng/mL (MESI-IMS) for α-pinene). These three analytical systems were applied for on-site rapid determination of acetone in human breath and α-pinene from plant emissions respectively. The salient features of these systems that make them suitable for on-site monitoring of volatile organic compounds in different sources are: small size, simple operation, fast and/or on-line sampling, rapid analysis.

The diploma thesis is focused on the development of in-line micro-electromembrane extraction (EME) coupled to capillary electrophoresis (CE) for the analysis of selected drugs in body fluids. Up to now, direct coupling of EME to CE has been demonstrated on diluted river samples only [1]. Although the published set-up has been implemented within a commercial CE it suffers from several drawbacks that can have a negative impact on the analysis of samples with higher complexity. The instrumental arrangement presented in this thesis eliminates these deficiencies. The experimental part is based on the optimization of fundamental extraction and separation conditions for the analysis of model basic drugs (nortriptyline, haloperidol, loperamide) with the use of transient isotachophoresis (tITP) principle. The extraction conditions were optimized for electro-driven transport of basic analytes from complex matrices (urine) through free liquid membrane followed by injection step utilized by electrokinetic supercharging (EKS), which focused target analytes into the CE capillary. Optimized conditions have been applied on blood in the form of dry blood spots, which are highly attractive samples in the current clinical analysis. The repeatability of the measurements was

Bioanalytical chemistry is a challenging field, often involving complex samples, such as blood, plasma, serum or urine. In many applications, sample cleanup is the most demanding and time-consuming step. In the work underlying this thesis a novel dynamic miniature extractor, known as a hollow-fibre liquid-phase microextractor (HF-LPME), was designed, evaluated and studied closely when used to clean plasma samples. Aqueous-organic-aqueous liquid extraction, in which the organic liquid is immobilised in a porous polypropylene membrane, was the principle upon which the extractor was based, and this is discussed in all the papers associated with this thesis. This type of extraction is known as supported-liquid membrane extraction (SLM). The aim of this work was the development of a dynamic system for SLM. It was essential that the system could handle small sample volumes and had the potential for hyphenations and on-line connections to, for instance, LC/electrospray-MS. The design of a miniaturised HF-LPME device is presented in Paper I. The extraction method was developed for some weakly acidic pesticides and these were also used for evaluation. In the work described in Paper II, the method was optimised on the basis of an experimental design using spiked human plasma samples. Paper III presents a detailed study of the mass-transfer over the liquid membrane. The diffusion through the membrane pores was illustrated by a computer-simulation. Not surprisingly, the more lipophilic, the greater the retention of the compounds, as a result of dispersive forces. The main focus of the work described in Paper IV was to make the HF/LPME system more versatile and user-friendly; therefore, the extractor was automated by hyphenation to a SIA system. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript.

This thesis focuses on low-cost microextraction techniques and their application for purification and preconcentration of biological samples, specifically on the experimental study of supported liquid membrane (SLM) extraction. The described microextraction technique uses commercially available filtration plates as the extraction units and allows the extraction of basic drugs from biological samples of urine and blood (in the form of dried blood spots). The experimental part includes the optimization of microextraction conditions of basic drugs from real samples through a SLM coupled in-line to lab-made capillary electrophoresis. The basic optimization of microextraction conditions involved selecting the appropriate organic phase for membrane impregnation (1:1 mixture of ENB and DHE), appropriate agitation speed for sample convection during extraction (1000 rpm), and optimal ratio of donor to acceptor volumes for high preconcentration of the analytes (400:15 µL). After basic optimization, the effect of donor alkalization with NaOH on extraction recovery (ER) was investigated. For all matrices used (saline solution, undiluted human urine samples, human capillary blood eluted from dry blood spots with deionized water), the highest ER values were achieved using a neutral donor and an acidic acceptor. The extraction time (60 minutes) was optimized based on the time profile of the microextraction for 120 minutes. This optimized microextraction method is suitable for the determination of basic drugs in real matrices with sufficient sample clean-up, preconcentration and ER values.