Development and evaluation of a new in vivo solid-phase microextraction sampler

Recent Applications of Solid Phase Microextraction Coupled to Liquid Chromatography

Solid phase microextraction (SPME) is one of the most popular sample preparation methods which can be applied to organic compounds allowing the simultaneous extraction and pre-concentration of analytes from the sample matrix. It is based on the partitioning of the analyte between the extracting phase, generally immobilized on a fiber substrate, and the matrix (water, air, etc.), and has numerous advantages such as rapidity, simplicity, low cost, ease of use and automation, and absence of toxic solvents. Fiber SPME has been widely used in combination with various analytical instrumentation even if most of the work has been done coupling the extraction technique with gas and liquid chromatography (GC and LC). This manuscript presents an overview of the recent works (from 2010 to date) of solid phase microextraction coupled to liquid chromatography (SPME-LC) relevant to analytical applications performed using commercially available fibers or lab-made fibers already developed in previous papers, and to improved instrumental systems and approaches.

In vivo solid-phase microextraction sampling combined with metabolomics and toxicological studies for the non-lethal monitoring of the exposome in fish tissue

Various environmental studies have employed the biomonitoring of fish in their aquatic ecosystems in order to identify potential metabolic responses to the exposome. In this study, we applied in vivo solid-phase microextraction (SPME) to perform non-lethal sampling on the muscle tissue of living fish to extract toxicants and various endogenous metabolites. Sixty white suckers (Catastomus commersonii) were sampled from sites upstream, adjacent, and downstream from the oil sands development region of the Athabasca River (Alberta, Canada) in order to track their biochemical responses to potential contaminants. In vivo SPME sampling facilitated the extraction of a wide range of endogenous metabolites, mainly related to lipid metabolism. The obtained results revealed significant changes in the levels of numerous metabolites, including eicosanoids, linoleic acids, and fat-soluble vitamins, in fish sampled in different areas of the river, thus demonstrating SPME's applicability for the direct monitoring of exposure to different environmental toxicants. In addition, several classes of toxins, including petroleum-related compounds, that can cause serious physiological impairment were tentatively identified in the extracts. In vivo SPME, combined with the analysis of contaminants and endogenous metabolites, provided important information about the exposome; as such, this approach represents a potentially powerful and non-lethal tool for identifying the mechanisms that produce altered metabolic pathways in response to the mixtures of different environmental pollutants.

Solid-phase microextraction: An appealing alternative for the determination of endogenous substances - A review

The determination of endogenous substances is of great significance for obtaining important biotic information such as biological components, metabolic pathways and disease biomarkers in different living organisms (e.g. plants, insects, animals and humans). However, due to the complex matrix and the trace concentrations of target analytes, the sample preparation procedure is an essential step before the analytes of interest are introduced into a detection instrument. Solid-phase microextraction (SPME), an emerging sample preparation technique that integrates sampling, extraction, concentration, and sample introduction into one step, has gained wide acceptance in various research fields, including in the determination of endogenous compounds. In this review, recent developments and applications of SPME for the determination of endogenous substances over the past five years are summarized. Several aspects, including the design of SPME devices (sampling configuration and coating), applications (in vitro and in vivo sampling), and coupling with emerging instruments (comprehensive two-dimensional gas chromatography (GC × GC), ambient mass spectrometry (AMS) and surface enhanced Raman scattering (SERS)) are involved. Finally, the challenges and opportunities of SPME methods in endogenous substances analysis are also discussed.

New techniques of on-line biological sample processing and their application in the field of biopharmaceutical analysis

Biological sample pretreatment is an important step in biological sample analysis. Due to the diversity of biological matrices, the analysis of target substances in these samples presents significant challenges to sample processing. To meet these emerging demands on biopharmaceutical analysis, this paper summarizes several new techniques of on-line biological sample processing: solid phase extraction, solid phase micro-extraction, column switching, limited intake filler, molecularly imprinted solid phase extraction, tubular column, and micro-dialysis. We describe new developments, principles, and characteristics of these techniques, and the application of liquid chromatography–mass spectrometry (LC–MS) in biopharmaceutical analysis with these new techniques in on-line biological sample processing.

Solid-phase microextraction technology for in vitro and in vivo metabolite analysis

Analysis of endogenous metabolites in biological samples may lead to the identification of biomarkers in metabolomics studies. To achieve accurate sample analysis, a combined method of continuous quick sampling and extraction is required for online compound detection. Solid-phase microextraction (SPME) integrates sampling, extraction and concentration into a single solvent-free step for chemical analysis. SPME has a number of advantages, including simplicity, high sensitivity and a relatively non-invasive nature. In this article, we reviewed SPME technology in in vitro and in vivo analyses of metabolites after the ingestion of herbal medicines, foods and pharmaceutical agents. The metabolites of microorganisms in dietary supplements and in the gastrointestinal tract will also be examined. As a promising technology in biomedical and pharmaceutical research, SPME and its future applications will depend on advances in analytical technologies and material science.

A comparative study of primary secondary amino (PSA) and multi-walled carbon nanotubes (MWCNTs) as QuEChERS absorbents for the rapid determination of diazepam and its major metabolites in fish samples by high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry

BACKGROUND

A simple and fast modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method is presented for the determination of diazepam and its three major metabolites, nordiazepam, temazepam and oxazepam (benzodiazepines) in fish samples by liquid chromatography-electrospray ionisation-tandem mass spectrometry.

RESULTS

Muscle tissues were extracted with acetonitrile, and then cleaned with primary secondary amino (PSA) adsorbents. The cleanup effect of PSA was compared with that of multi-walled carbon nanotubes (MWCNTs) in term of extraction efficiency. The better results were obtained when PSA was used. The chromatography separation was achieved within 5.0 min on a C18 column. The limit of detection was 0.5 µg kg(-1) and the limit of quantification was 2.5 µg kg(-1). Average recoveries of diazepam and its main metabolites were in the range of 88.5-110.1%, with a relative standard deviation lower than 10.0%.

CONCLUSION

The proposed method for fish samples gives good recoveries, linearity, precision and accuracy.

Evaluation of a multi-fiber exchange solid-phase microextraction system and its application to on-site sampling

Until recently, multiple solid-phase microextraction fibers could not be automatically desorbed in a single gas chromatographic sequence without manual intervention from an operator. This drawback had been a critical issue, particularly during the analysis of numerous on-site samples taken with various fiber assemblies. Recently, a Multi-Fiber Exchange system, designed to overcome this flaw found in other commercially available autosamplers, was released. In the current research, a critical evaluation of the Multi-Fiber Exchange system performance in terms of storage stability and long-term operation is presented. It was established in the course of our research that the Multi-Fiber Exchange system can operate continuously and precisely for multiple extraction/injection cycles. However, when the effect of residence time of commercial fibers on the Multi-Fiber Exchange tray was evaluated, results showed that among the evaluated fiber coatings, Carboxen/polydimethylsiloxane was the only coating capable of efficient storage on the tray for up to 24 h after field sampling without suffering significant loss of analytes (≤10% for benzene, toluene, ethylbenzene, o-xylene, decane, and limonene). Additionally, the system capability for high-throughput analysis was demonstrated by the unattended desorption of multiple fibers after on-site sampling of toluene, indoor air levels, in a polymer synthesis lab.

In vivo determination of the volatile metabolites of saprotroph fungi by comprehensive two-dimensional gas chromatography

In this work, we discuss the use of multiway principal component analysis combined with comprehensive two-dimensional gas chromatography to study the volatile metabolites of the saprophytic fungus Memnoniella sp. isolated in vivo by headspace solid-phase microextraction. This fungus has been identified as having the ability to induce plant resistance against pathogens, possibly through its volatile metabolites. Adequate culture media were inoculated, and its headspace was then sampled with a solid-phase microextraction fiber and chromatographed every 24 h over seven days. The raw chromatogram processing using multiway principal component analysis allowed the determination of the inoculation period, during which the concentration of volatile metabolites was maximized, as well as the discrimination of the appropriate peaks from the complex culture media background. Several volatile metabolites not previously described in the literature on biocontrol fungi were observed, as well as sesquiterpenes and aliphatic alcohols. These results stress that, due to the complexity of multidimensional chromatographic data, multivariate tools might be mandatory even for apparently trivial tasks, such as the determination of the temporal profile of metabolite production and extinction. However, when compared with conventional gas chromatography, the complex data processing yields a considerable improvement in the information obtained from the samples.

In vivo and ex vivo SPME: a low invasive sampling and sample preparation tool in clinical bioanalysis

Solid phase microextraction (SPME) is well-established technology in bioanalysis. Current review discusses the features of SPME, which determine the non- or low-invasiveness of the method in biomedical analysis. In the first section we analyze the factors, which have significant influence on the SPME sampling device performance in the view of sampling safety and efficiency. In the later sections applicability of various SPME approaches for analysis of easily accessible samples routinely used for analysis (e.g., urine, blood) as well as limited availability samples (tissues) is discussed. Moreover, the examples of sampling alternative matrices such as hair, saliva, sweat or breath are presented. The advantages and limitation of the technology in the view of future development of SPME are also reviewed.

Low invasive in vivo tissue sampling for monitoring biomarkers and drugs during surgery

The techniques currently used for drug, metabolite, and biomarker determination are based on sample collection, and therefore they are not suitable for repeated analysis because of the high invasiveness. Here, we present a novel method of biochemical analysis directly in organ during operation without need of a separate sample collection step: solid-phase microextraction (SPME). The approach is based on flexible microprobe coated with biocompatible extraction phase that is inserted to the tissue with no damage or disturbance of the organ. The method was evaluated during lung and liver transplantations using normothermic ex vivo liver perfusion (NEVLP) and ex vivo lung perfusion (EVLP). The study demonstrated feasibility of the method to extract wide range of endogenous compounds and drugs. Statistical analysis allowed observing metabolic changes of lung during cold ischemic time, perfusion, and reperfusion. It was also demonstrated that the level of drugs and their metabolites can be monitored over time. Based on the methylprednisolone as a selected example, the impairment of enzymatic properties of liver was detected in the injured organs but not in healthy control. This finding was supported by changes in pathways of endogenous metabolites. The SPME probe was also used for analysis of perfusion fluid using stopcock connection. The evaluation of biochemical profile of perfusates demonstrated potential of the approach for monitoring organ function during ex vivo perfusion. The simplicity of the device makes it convenient to use by medical personnel. With the microprobe, different areas of the organ or various organs can be sampled simultaneously. The technology allows assessment of organ function by biochemical profiling, determination of potential biomarkers, and drug monitoring. The use of this method for preintervention analysis could enhance the decision-making process for the best possible personalized approach, whereas post-transplantation monitoring would be used for graft assessments and fast response in case of organ failure.

Recent advances in unique sample preparation techniques for bioanalysis

The extraction and/or purification of drugs and medicines from biological matrices are important objectives in investigating their toxicological and pharmaceutical properties. Many widely used methods such as liquid–liquid extraction or SPE, used for extracting, purifying and enriching drugs and medicines found in biological materials, involve laborious, intensive and expensive preparatory procedures, and they require organic solvents that are toxic to both humans and the environment. Recent trends are focused on miniaturization, high-throughput and automation techniques. All the advantages and disadvantages of these techniques and devices in biological analysis are presented, and their applications in the extraction and/or purification of drugs and medicines from biological matrices are discussed in this review.