In-tube solid-phase microextraction (in-tube SPME) with capillary column as extraction device allows direct coupling to high performance liquid chromatography (HPLC) systems. This technique ...associates the advantages of on-line systems with the advantages of miniaturized systems. Since its development, in-tube SPME has been continuously improved. New couplings have also been evaluated on the basis of state-of-the-art HPLC instruments. Major achievements include the development of new capillary coatings to enhance the in-tube SPME performance (sorption capacity and selectivity). Innovative SPME fibers (fiber in-tube SPME) and capillary coatings based mainly on monolithic, nanoparticles, ionic liquids, carbon, and hybrid materials have been evaluated. This review provides an overview of the fundamental theory and current advances concerning in-tube SPME systems and highlights their main applications in environmental, clinical, and food analyses.
•Overview of the fundamental theory and current advances concerning in-tube SPME systems.•Main applications of in-tube SPME in environmental, clinical, and food analyses.•Innovative SPME fibers and capillary coatings are discussed.•New couplings on the basis of state-of-the-art HPLC instruments.
In‐tube solid‐phase microextraction with a capillary column as extraction device can be directly coupled with high‐performance liquid chromatography systems (HPLC). The in‐tube solid‐phase ...microextraction technique has been continuously developed since it was introduced in 1997. New couplings have also been evaluated on the basis of state‐of‐the‐art HPLC instruments. Different types of capillaries (wall‐coated open tubular, porous layer open tubular, sorbent‐packed, porous monolithic rods, or fiber‐packed) with selective stationary phases (monoliths, magnetic nanoparticles, conducting polymers, restricted access materials, ionic liquids, carbon, deep eutectic solvents, and hybrid materials) have been developed to boost in‐tube solid‐phase microextraction performance (sorption capacity and selectivity). This technique has been successfully applied to analyze biological samples (serum, plasma, whole blood, hair, urine, milk, skin, and saliva) for therapeutic drug monitoring, to study biomarkers, to detect illicit drugs, to conduct metabolomics studies, and to assess exposure to drugs. This review describes current advances in in‐tube solid‐phase microextraction extraction devices and their application in bioanalysis.
This study reports a fast, sensitive, and selective column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to determine the endocannabinoids ...(eCBs), anandamide (AEA), and 2-arachidonoylglycerol (2-AG) in plasma samples. This bidimensional system used a restricted access media column (RP-8 ADS, 25 mm × 4 mm × 25 μM) in the first dimension and a core-shell Kinetex C18 (100 mm × 2, 1.7 mm × 1 μM) column in the second dimension, followed by detection in a mass spectrometer triple quadrupole (multiple reactions monitoring mode) operating in the positive mode. RP-8 ADS was used for trace enrichment of eCBs (reverse phase partitioning) and macromolecular matrix size exclusion; the core-shell column was used for the chromatographic separation. The column switching UHPLC-MS/MS method presented a linear range spanning from 0.1 ng mL
−1
(LOQ) to 6 ng mL
−1
for AEA and from 0.04 ng mL
−1
(LOQ) to 10 ng mL
−1
for 2-AG. Excluding the LLOQ values, the precision assays provided coefficients of variation lower than 8% and accuracy with relative standard error values lower than 14%. Neither carryover nor matrix effects were detected. This high-throughput column switching method compared to conventional methods is time saving as it involves fewer steps, consumes less solvent, and presents lower LLOQ. The column switching UHPLC-MS/MS method was successfully applied to determine AEA and 2-AG in plasma samples obtained from Alzheimer’s disease patients.
Graphical abstract
A column switching ultra high-performance liquid chromatography-tandem mass spectrometry method using RP-8 ADS column and core shell column to determine endocannabinoids in plasma samples
In vivo solid phase microextraction for bioanalysis Queiroz, Maria Eugênia Costa; Souza, Israel Donizeti de; Oliveira, Igor Gustavo de ...
TrAC, Trends in analytical chemistry (Regular ed.),
August 2022, 2022-08-00, Letnik:
153
Journal Article
Recenzirano
Solid phase microextraction (SPME) is a rapid, well-established, and solvent-free sample preparation technique. It has usually been hyphenated with GC-MS or LC-MS/MS to separate and to detect ...enriched analytes. In recent years, ambient ionization techniques have been developed fast. This has allowed MS to be used for direct and straightforward SPME analysis of complex samples, dismissing the need for chromatographic separation. SPME sampling disturbs systems to a minimum—it removes (extracts) only small fractions of analytes. Therefore, in vivo analysis is a special application area where SPME is gaining ground.
This review summarizes state-of-the-art in vivo SPME for bioanalysis (in human, rats, fishes, rhesus macaque, frog, and living cattle), including biocompatible SPME coatings, sampling approaches for in vivo SPME (skin, exhaled breath, saliva, blood, muscle, and brain sampling), analytical/detection systems, and calibration methods. This review also discusses in vivo SPME applications (pharmacokinetic studies, exposure, biomarkers, diagnosis, doping control, lipidomics, drug analysis, cosmetic dermatology, bioaccumulation, biomonitoring, environmental pollutants, and therapeutic drug monitoring) and future trends in in vivo SPME bioanalysis.
•State-of-the-art in vivo SPME for bioanalysis.•In vivo SPME applications.•Future trends in in vivo SPME bioanalysis.
•Miniaturized liquid chromatography has been applied in several research fields.•Online coupling of sample preparation techniques with miniaturized systems improve the analytical efficiency.•Online ...systems boost analytical performance and sensitivity.•Online miniaturized LC configurations, innovative sorbents, and applications are described.
Miniaturized liquid chromatography (LC) has been recognized as one of the most important analytical methods in several research fields. Reduced analytical work-scale provides superior chromatographic resolution and decreases sample and organic solvent consumption. However, frequent clogging of tubing connections and use of small sample volumes are significant limitations when high throughput and sensitive analyses are required. Effective sample preparation could help to overcome these limitations. Online coupling of sample preparation techniques (such as column switching and in-tube solid-phase microextraction) with these miniaturized systems may result in more sensitive and reproducible analyses, improving analytical efficiency. This review describes the most common online miniaturized LC configurations, and the main applications of current online sample preparation techniques coupled to miniaturized LC systems in the bioanalytical, omics, and environmental areas. Relevant features, and challenges of these systems, and innovative sorbents, including restricted access materials, monoliths, and immunosorbents is also discussed.
Endocannabinoids (ECs) are endogenous lipid-based retrograde neurotransmitters that bind to cannabinoid receptors cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). Many ECs have been ...characterized; anandamide (AEA) and 2-arachidonoyl glycerol (2-AG) are still considered the primary ECs signaling mediators. Dysregulation of ECs has been implicated in a wide range of pathologies, including neurodegenerative diseases. Understanding how ECs participate in neurological diseases is important to describe the pathology and to establish new treatments. Considering the physicochemical properties of ECs, liquid chromatography coupled to tandem mass spectrometry has become the reference method to determine these endogenous substances, in trace levels, in different biological samples. This review describes the recent advances in LC-MS/MS methods designed to determine ECs in complex biological matrixes. The advantages, limitations, selectivity, matrix effect, and sensitivity associated with each approach are emphasized. This article comprises three sections: (I) sample preparation techniques (conventional, microextraction, and online systems), (II) chromatographic methods (especially LC-MS/MS), and (III) relationship between ECs levels and neurodegenerative diseases.
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•Recent advances in LC-MS/MS methods designed to determine ECs, AEA and.2-AG, in complex matrixes.•Sample preparation techniques (conventional, microextraction, and online systems).•ECs levels correlated with neurodegenerative diseases.
•In-tube SPME direct coupling with MS/MS to determine endocannabinoids in rat brain•In-tube SPME (RAM phase) efficiently excluded macromolecules from brain samples•Optimization of in-tube SPME ...parameters improved extraction performance•Due to the method selectivity, the chromatographic separation step was not required•The method allowed the study of endocannabinoid system on Parkinson's disease
To evaluate the endocannabinoid system in an animal model of Parkinson's disease, in-tube solid-phase microextraction (in-tube SPME) was directly coupled to a tandem mass spectrometry (MS/MS) system for determination of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) in rat brain samples. In-tube SPME—which consisted of a microtube of restricted access material (RAM) with a hydrophilic diol external surface and a hydrophobic octyl inner surface—efficiently excluded (up to 95%) macromolecules from the biological samples and selectively pre-concentrated the analytes. In-tube SPME parameters, such as sample volume, mobile phases, flow rate, and pre-concentration time, were evaluated to improve the extraction efficiency and throughput performance. The selectivity of the in-tube SPME and MS/MS (MRM mode) techniques allowed them to be directly coupled online, which dismissed the need for the chromatographic separation step. The in-tube SPME-MS/MS method was validated and shown to be linear from 6.0 to 30.0 ng mL−1 for AEA and from 10.0 to 100.0 ng mL−1 for 2-AG; the intra- and inter-assay accuracy and precision were lower than 15%. Parallelism between the calibration curves constructed in the matrix and aqueous solution confirmed that there was no matrix effect. The method allowed endogenous concentrations of AEA and 2-AG to be determined in rat brain striatum from unilaterally 6-hydroxydopamine-lesioned animals. The concentrations of these endocannabinoids in striatum ipsilateral and contralateral to the lesion differed significantly (p<0.001).
•Development of the selective organic–inorganic hybrid cyanopropyl monolithic for bioanalysis.•This capillary was reused more than 100 times as sorbent for column-switching.•The high permeability of ...the monolithic capillary facilitated the biological sample percolation.•Column-switching LC-MS/MS system for therapeutic drug monitoring in patients with schizophrenia.•The column-switching LC-MS/MS method presented LLOQs values at sub-therapeutic levels.
This study reports on the development of a rapid, selective, and sensitive column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze sixteen drugs (antidepressants, anticonvulsants, anxiolytics, and antipsychotics) in plasma samples from schizophrenic patients. The developed organic-inorganic hybrid monolithic column with cyanopropyl groups was used for the first dimension of the column-switching arrangement. This arrangement enabled online pre-concentration of the drugs (monolithic column) and their subsequent analytical separation on an XSelect SCH C18 column. The drugs were detected on a triple quadrupole tandem mass spectrometer (multiple reactions monitoring mode) with an electrospray ionization source in the positive ion mode. The developed method afforded adequate linearity for the sixteen target drugs; the coefficients of determination (R2) lay above 0.9932, the interassay precision had coefficients of variation lower than 6.5%, and the relative standard error values of the accuracy ranged from −14.0 to 11.8%. The lower limits of quantification in plasma samples ranged from 63 to 1250pgmL−1. The developed method successfully analyzed the target drugs in plasma samples from schizophrenic patients for therapeutic drug monitoring (TDM).
Since it was introduced in 1997, in-tube solid-phase microextraction (in-tube SPME), which uses a capillary column as extraction device, has been continuously developed as online microextraction ...coupled to LC systems (in-tube SPME-LC). In the last decade, new couplings have been evaluated on the basis of state-of-the-art LC instruments, including direct coupling of in-tube SPME to MS/MS systems, without chromatographic separation, for high-throughput analysis. In-tube SPME coupling to MS/MS has been possible thanks to the selectivity of capillary column coatings and MS/MS systems (SRM mode). Different types of capillary columns (wall-coated open-tubular, porous-layer open-tubular, sorbent-packed, porous monolithic rods, or fiber-packed) with selective stationary phases have been developed to increase the sorption capacity and selectivity of in-tube SPME. This review focuses on the in-tube SPME principle, extraction configurations, current advances in direct coupling to MS/MS systems, experimental parameters, coatings, and applications in different areas (food, biological, clinical, and environmental areas) over the last years.
•A fiber-in-tube SPME-CapLC-MS/MS method was developed.•The reduced flow rate increased the sensitivity due to better desolvation of the analytes.•The method developed here was compared with the ...fiber-in-tube SPME-LC-MS/MS (performed on a conventional scale).•The use of a chromatography column was significant not only to focus the analytes in the column.
Mass spectrometry is characterized by its high sensitivity, ability to measure very low analyte concentrations, specificity to distinguish between closely related compounds, availability to generate high-throughput methods for screening, and high multiplexing capacity. This technique has been used as a platform to analyze fluid biomarkers for Alzheimer's disease. However, more effective sample preparation procedures, preferably antibody-independent, and more automated mass spectrometry platforms with improved sensitivity, chromatographic separation, and high throughput are needed for this purpose. This short communication discusses the development of a fiber-in-tube SPME-CapLC-MS/MS method to determine Aβ peptides in cerebrospinal fluid obtained from Alzheimer's disease patients. To obtain the fiber-in-tube SPME capillary, we longitudinally packed 22 nitinol fibers coated with a zwitterionic polymeric ionic liquid into the same length of the PEEK tube. In addition, this communication compares this fiber-in-tube SPME method with the conventional HPLC scale (HPLC-MS/MS) and when directly coupled to CapESI-MS/MS without chromatographic separation, and, as a case study, discusses the benefits and challenges inherent in miniaturizing the flow scale of the sample preparation technique (fiber-in-tube SPME) to the CapLC-MS/MS system. Fiber-in-tube SPME-CapLC-MS/MS provided LLOQ ranging from 0.09 to 0.10 ng mL−1, accuracy ranging from 91 to 117 % (recovery), and reproducibility of less than 18 % (RSD). Analysis of the cerebrospinal fluid samples obtained from Alzheimer's disease patients evidenced that the method is robust. At the capillary scale (10 µL min−1), this innovative method presented higher analytical sensitivity than the conventional HPLC-MS/MS scale. Although fiber-in-tube SPME directly coupled to CapESI-MS/MS offers advantages in terms of high throughput, the sample was dispersed and non-quantitatively desorbed from the capillary at low flow rate. These results highlighted that chromatographic separation is important to decrease the matrix effect and to achieve higher detectability, which is indispensable for bioanalysis.
