High throughput determination of free biogenic monoamines and their metabolites in urine using thin-film solid phase microextraction

Hydrophilic-lipophilic balance copolymer composite nanofiber as an adsorbent for online solid phase extraction of three estrogens from water samples with column-switching prior to high-performance liquid chromatography

BACKGROUND

In recent years, the increasing accumulation of estrogen pollutants in the environment has raised concerns about their impact on human health, necessitating the development of highly sensitive detection methods for trace pollutant enrichment and analysis in environmental samples. Online pretreatment detection technology offers significant advantages over conventional offline techniques, including high automation, minimal human intervention, and improved efficiency. However, the key to successful implementation lies in the advancement of novel adsorbent materials.

RESULTS

Herein, we present a novel adsorbent material called polyacrylonitrile-hydrophilic-lipophilic balanced copolymer (PAN-HLB) composite nanofiber prepared via electrospinning for efficient online packed fiber solid phase extraction (PFSPE) of three estrogens from water samples. A rapid and highly sensitive online PFSPE-HPLC-FLD method was developed for the quantification of 17 β-Estradiol (E2), Estriol (E3), and 17-ethinylestradiol (EE2). The curves of the target analytes were prepared with good correlation coefficient values (r2 > 0.9900) in the range of 0.1-2 ng/mL. The limit of detection (S/N = 3) was 0.05 ng/mL, the limit of quantitation (S/N = 10) is 0.1 ng/mL. The recoveries of three estrogens were 94.0 %∼110.3 %, and the precisions (RSD) were less than 5 %. The online PFSPE column, packed with the PAN-HLB composite nanofiber, exhibits exceptional stability and can be effectively reused for a minimum of 100 cycles.

SIGNIFICANCE

This study presents the successful preparation of PAN-HLB composite nanofiber for the first time, demonstrating their efficacy as an innovative online pretreatment adsorbent. The proposed online pretreatment and detection approach offers remarkable benefits in terms of sensitivity, labor-saving, and cost-effectiveness that make it highly suitable for practical water sample analysis.

New Materials for Thin-Film Solid-Phase Microextraction (TF-SPME) and Their Use for Isolation and Preconcentration of Selected Compounds from Aqueous, Biological and Food Matrices

Determination of a broad spectrum of analytes, carried out with analytical instruments in samples with complex matrices, including environmental, biological, and food samples, involves the development of new and selective sorption phases used in microextraction techniques that allow their isolation from the matrix. SPME solid-phase microextraction is compatible with green analytical chemistry among the sample preparation techniques, as it reduces the use of toxic organic solvents to the minimum necessary. Over the past two decades, it has undergone impressive progress, resulting in the development of the thin-film solid-phase microextraction technique, TF-SPME (the thin-film solid-phase microextraction), which is characterized by a much larger surface area of the sorption phase compared to that of the SPME fiber. TF-SPME devices, in the form of a mostly rectangular metal or polymer substrate onto which a thin film of sorption phase is applied, are characterized, among others, by a higher sorption capacity. In comparison with microextraction carried out on SPME fiber, they enable faster microextraction of analytes. The active phase on which analyte sorption occurs can be applied to the substrate through techniques such as dip coating, spin coating, electrospinning, rod coating, and spray coating. The dynamic development of materials chemistry makes it possible to use increasingly advanced materials as selective sorption phases in the TF-SPME technique: polymers, conducting polymers, molecularly imprinted polymers, organometallic frameworks, carbon nanomaterials, aptamers, polymeric ionic liquids, and deep eutectic solvents. Therefore, TF-SPME has been successfully used to prepare analytical samples to determine a broad spectrum of analytes in sample matrices: environmental, biological, and food. The work will be a review of the above-mentioned issues.

Boric Acid Functionalized Hypercrosslinked Polymers for Selective Extraction of Trace Catecholamines and Their Metabolites in Rat Serum

Abnormal levels of catecholamine (CA) neurotransmitters and their metabolites in biological fluids can lead to various neurological disorders. Herein, a boric acid-functionalized hypercrosslinked polymer was prepared and utilized as a sorbent for the dispersive solid-phase extraction of CAs and their metabolites in rat serum. By combination with a high-performance liquid chromatography-fluorescence detector, the extraction parameters for the seven target analytes were optimized. Under the optimal extraction condition, the methodology for the quantitative analysis of CAs and their metabolites in rat serum samples was established. The limits of detection and limits of quantification were found to be in the ranges of 0.010-0.015 and 0.033-0.050 ng/mL, respectively. The results demonstrated satisfactory recoveries, with values ranging from 88.02% to 113.27%, accompanied by relative standard deviations within the range of 2.69%-9.59%. In addition, the method showed good anti-interference ability (matrix effect ranged from 2.64% to 18.07%). The developed method was validated for the determination of CAs and their metabolites in normal and Alzheimer's disease model rats' serum, which proved the promising application of the method for CAs neurotransmitter analysis in biological samples.

Clinical diagnosis of pheochromocytoma and paraganglioma-induced secondary hypertension through UPLC-MS/MS analysis of plasma catecholamines and their metabolites

This study aimed to elucidate the clinical diagnostic value of plasma catecholamines and their metabolites for pheochromocytoma and paraganglioma (PPGL)-induced secondary hypertension using ultraperformance liquid chromatography-mass spectrometry (UPLC-MS/MS). The study population included 155 patients with PPGL that were divided into the PPGL with hypertension (n = 79) and a PPGL without hypertension (n = 76) groups, and 90 healthy volunteers and 90 patients with primary hypertension as the control groups. UPLC-MS/MS was performed to detect plasma levels of catecholamines and their metabolites, including dopamine, vanillylmandelic acid (VMA), norepinephrine, metanephrine, and normetanephrine. Receiver operating characteristic curves were generated to analyze the diagnostic value of the plasma levels of catecholamines and their metabolites in PPGL-induced secondary hypertension. Patients in the primary hypertension and PPGL without hypertension groups had higher levels of dopamine, VMA, norepinephrine, metanephrine, and normetanephrine than patients in the normal group (all p < .05). On the other hand, patients in the PPGL with hypertension group had higher levels of dopamine, VMA, norepinephrine, metanephrine, and normetanephrine than patients in the normal, primary hypertension, and PPGL without hypertension groups (all p < .05). Collectively, our findings showed that dopamine, VMA, norepinephrine, metanephrine, and normetanephrine are all effective biomarkers for the diagnosis of PPGL and PPGL-induced secondary hypertension.

Embedding Mixed Sorbents in Binder: Solid-Phase Microextraction Coating with Wide Extraction Coverage and Its Application in Environmental Water Analysis

Solid-phase microextraction (SPME) is a simple and highly effective sample-preparation technique for water analysis. However, the extraction coverage of a given SPME device with a specific coating can be an issue when analyzing multiple environmental contaminants. Therefore, instead of synthesizing one sorbent material with dual or multiple functions, we investigated a new strategy of preparing SPME blades using a homogeneous slurry made by mixing three different sorbent particles─namely, hydrophobic/lipophilic balanced (HLB), HLB-weak cationic exchange (HLB-WCX), and HLB-weak anionic exchange (HLB-WAX)─with a polyacrylonitrile (PAN) binder. The developed coating is matrix compatible, as the binder functions not only as a glue for immobilizing the sorbent particles but also as a porous filter, which only allows small molecules to enter the pores and interact with the particles, thus avoiding contamination from large elements. The results confirmed that the proposed mixed-coating SPME device provides good extraction performance for polar and nonpolar as well as positively and negatively charged compounds. Based on this device, three comprehensive analytical methodologies─high-throughput SPME-LC-MS/MS (for the quantitative analysis of targeted drugs of abuse and artificial sweeteners), in-bottle SPME-LC-high resolution MS (HRMS) (for the untargeted screening of organic contaminants), and on-site drone sampling SPME-LC-HRMS (for on-site sampling and untargeted screening)─were developed for use in environmental water analysis. The resultant data confirm that the proposed strategies enable comprehensive water quality assessment by using a single SPME device.

TiO2@COF-based solid-phase microextraction combined with UHPLC-MS/MS for the rapid determination of potential biomarkers of phosphatidylcholines and lysophosphatidylcholines in head and neck cancers

Phosphatidylcholine (PC) and lysophosphatidylcholine (LPC), two types of phospholipids (PLs), have been reported to be closely correlated with head and neck cancers of laryngeal cancer (LC) and thyroid cancer (TC), which make their analysis crucial. TiO2@COF-based solid-phase microextraction (SPME) coupled to UHPLC-MS/MS was developed for the rapid and accurate detection of seven potential PL biomarkers from small amounts of serum in this work. The combination of TiO2 and COF proves to be effective for the extraction of the target analytes. Under optimal conditions, the developed TiO2@COF-based SPME-UHPLC-MS/MS method revealed good linearity (R2 ≥ 0.997) with LODs ranging from 0.05 to 0.38 ng/mL for PLs, the extraction recoveries and matrix effects ranging from 83.09-112.03% and 85.38-113.67%, respectively. As a high-throughput pretreatment method, satisfactory probe-to-probe reproducibility rates of 2.7-10.1% were obtained. Finally, the TiO2@COF-based SPME-UHPLC-MS/MS method was applied to analyze LPC 14:0, LPC 16:0, LPC 18:0, LPC 18:1, LPC 19:0, PC 16:0/18:1, and PC 18:0 in serum samples from early LC patients (n = 15), early TC patients (n = 15), and healthy volunteers (n = 15). The results indicated that cancer patients could be effectively differentiated from healthy controls using orthogonal partial least squares discriminant analysis (OPLS-DA). In conclusion, the established TiO2@COF-based SPME-UHPLC-MS/MS method is reliable for the rapid determination of the seven PLs in serum samples, which is promising for early diagnosis of head and neck cancers.

Recent Advances in Catecholamines Analytical Detection Methods and Their Pretreatment Technologies

Catecholamines (CAs), including adrenaline, noradrenaline, and dopamine, are neurotransmitters and hormones that play a critical role in regulating the cardiovascular system, metabolism, and stress response in the human body. As promising methods for real-time monitoring of catecholamine neurotransmitters, LC-MS detectors have gained widespread acceptance and shown significant progress over the past few years. Other detection methods such as fluorescence detection, colorimetric assays, surface-enhanced Raman spectroscopy, and surface plasmon resonance spectroscopy have also been developed to varying degrees. In addition, efficient pretreatment technology for CAs is flourishing due to the increasing development of many highly selective and recoverable materials. There are a few articles that provide an overview of electrochemical detection and efficient enrichment, but a comprehensive summary focusing on analytical detection technology is lacking. Thus, this review provides a comprehensive summary of recent analytical detection technology research on CAs published between 2017 and 2022. The advantages and limitations of relevant methods including efficient pretreatment technologies for biological matrices and analytical methods used in combination with pretreatment technology have been discussed. Overall, this review article provides a better understanding of the importance of accurate CAs measurement and offers perspectives on the development of novel methods for disease diagnosis and research in this field.

Mixed-mode cationic exchange sorptive tapes combined with direct infusion mass spectrometry for determining opioids in saliva samples

This article describes the synthesis of mixed-mode cationic exchange (MCX) tapes as sorptive phases in bioanalysis, and it faces the determination of methadone and tramadol in saliva as the model analytical problem. The tapes are synthesized using aluminum foil as substrate, which is subsequently covered with double-sided adhesive tape where the MCX particles (ca. 1.4 ± 0.2 mg) finally adhere. MCX particles allow the extraction of the analytes at the physiological pH, where both drugs are positively charged, minimizing the potential co-extraction of endogenous matrix compounds. The extraction conditions were studied considering the main variables (e.g. ionic strength, extraction time, sample dilution). Under the optimum conditions and using direct infusion mass spectrometry as the instrumental technique, detection limits as low as 3.3 μg·L^-1 were obtained. The precision calculated at three different levels, and expressed as relative standard deviation, was better than 3.8%. The accuracy, expressed as relative recoveries, ranged from 83 to 113%. The method was finally applied to determine tramadol in saliva samples from patients under medical treatment. This approach opens the door to easily preparing sorptive tapes based on commercial (or ad-hoc synthesized) sorbent particles.

PEG-modified halloysite as a hydrophilic interaction and cation exchange mixed-mode sorbent for solid-phase extraction of biogenic amines in fish samples

A novel type of PEG-modified halloysite was prepared and used as a hydrophilic interaction and cation exchange mixed-mode sorbent for solid-phase extraction of biogenic amines in fish samples. The eluates were analyzed by high-performance liquid chromatography-ultraviolet detection after the derivatization with benzoyl chloride. The developed sorbent was characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, zeta potential analyzer, and thermo-gravimetric analysis. After the optimization of various parameters influencing the extraction efficiency, the PEG-modified halloysite-based SPE method was evaluated. The adsorption capacities of putrescine, spermine, phenethylamine, and histamine were as high as 9.3, 8.5, 5.7, and 5.6 mg g-1, respectively. Satisfactory reproducibility of sorbent preparation was obtained with within-batch and batch-to-batch relative standard deviations (RSDs) lower than 3.9% and 8.6%, respectively. The biogenic amine spiking recoveries in fish samples ranged from 84.3 to 105.5% with good RSDs lower than 7.8%. Intra-day and inter-day precision, expressed as RSDs, were better than 8.8%. The limits of detection of histamine, putrescine, phenethylamine, and spermine were 9.4, 1.9, 0.5, and 0.9 μg L-1, respectively. This work provides a new hydrophilic interaction and cation exchange mixed-mode sorbent and is successfully applied to the extraction of trace biogenic amines from fish samples.

Composite Nanofibers as Novel Sorbents for On-Line and Off-Line Solid-Phase Extraction in Chromatographic System: A Comparison for Detection of Free Biogenic Monoamines and Their Metabolites in Plasma

Two different pretreatment approaches have been used for the enrichment and separation of biogenic monoamines and metabolites in plasma for high performance liquid chromatography (HPLC) determination. The first approach, based on on-line packed-fiber solid-phase extraction (PFSPE) coupled with HPLC, allows for the simultaneous detection of epinephrine (E), norepinephrine (NE), dopamine (DA), 3-methoxyl epinephrine (MN), norepinephrine (NMN), 3-methoxytyramine (3-MT), and 5-hydroxytryptamin (5-HT). Using this developed on-line PFSPE–HPLC method, the limit of detections (LODs) of the seven analytes ranged from 1 ng/mL (NMN and MN) to 2 ng/mL (NE, E, DA, 3-MT and 5-HT). The reportable ranges were 5–300 ng/mL for NE and DA, 5–100 ng/mL for E, and 5–200 ng/mL for NMN, MN, 3-MT and 5-HT. The off-line PFSPE–HPLC was employed in the second approach and could provide simultaneous detection of NE, E, DA, NMN, and MN. The linearity was verified in the range of 0.5–20 ng/mL (NE, E, and DA) and 20–250 ng/mL (NMN and MN). The LODs of the five analytes ranged from 0.2 ng/mL (NE, E, and DA) to 5 ng/mL (NMN and MN). This study verified the possibility of using nanofibers as an adsorbent in an on-line PFSPE–HPLC system for the determination of biogenic monoamines and their metabolites in human plasma. Compared with the off-line PFSPE approach, the on-line PFSPE method deserves attention mainly due to its greener character, derived from the automation of the process and high-throughput with less operators’ handling.

Simultaneous Determination of Methylated Nucleosides by HILIC-MS/MS Revealed Their Alterations in Urine from Breast Cancer Patients

RNA methylation plays a vital role in the pathogenesis of a variety of diseases including cancer, and aberrant levels of modified nucleosides in RNA were revealed to be related to cancer. Urine is a favored source for biomarker discovery due to the non-invasion to patients. Herein, we developed a sensitive hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC–MS/MS) method combined with stable isotope dilution for accurate quantification of methylated nucleosides in human urine. With this method, we successfully quantified ten methylated nucleosides in urine samples collected from healthy controls and breast cancer patients. We found N⁶-methyladenosine (m⁶A), 2′-O-methyladenosine (A_m), N¹-methyladenosine (m¹A), N⁶,2′-O-dimethyladenosine (m⁶A_m), N¹-methylguanosine (m¹G), 2′-O-methylguanosine (G_m), 5-methylcytidine (m⁵C) and 2′-O-methylcytidine (C_m) were all decreased in early-stage breast cancer patients, and a nomogram prediction model was constructed. Locally advanced breast cancer patients exhibited elevated levels of urinary 2′-O-methylated nucleosides in comparison to early-stage breast cancer patients. Together, we developed a robust method for the simultaneous determination of methylated nucleosides in human urine, and the results revealed an association between the contents of urinary methylated nucleosides and the occurrence of breast cancer, which may stimulate future studies about the regulatory roles of these methylated nucleosides in the initiation and progression of breast cancer.

Rapid and Wash-Free Time-Gated FRET Histamine Assays Using Antibodies and Aptamers

Histamine (HA) is an indicator of food freshness and quality. However, high concentrations of HA can cause food poisoning. Simple, rapid, sensitive, and specific quantification can enable efficient screening of HA in food and beverages. However, conventional assays are complicated and time-consuming, as they require multiple incubation, washing, and separation steps. Here, we demonstrate that time-gated Förster resonance energy transfer (TG-FRET) between terbium (Tb) complexes and organic dyes can be implemented in both immunosensors and aptasensors for simple HA quantification using a rapid, single-step, mix-and-measure assay format. Both biosensors could quantify HA at concentrations relevant in food poisoning with limits of detection of 0.19 μg/mL and 0.03 μg/mL, respectively. Excellent specificity was documented against the structurally similar food components tryptamine and l-histidine. Direct applicability of the TG-FRET assays was demonstrated by quantifying HA in spiked fish and wine samples with both excellent concentration recovery and agreement with conventional multistep enzyme-linked immunosorbent assays (ELISAs). Our results show that the simplicity and rapidity of TG-FRET assays do not compromise sensitivity, specificity, and reliability, and both immunosensors and aptasensors have a strong potential for their implementation in advanced food safety screening.

Current Sample Preparation Methodologies for Determination of Catecholamines and Their Metabolites

Catecholamines (CAs) and their metabolites play significant roles in many physiological processes. Changes in CAs concentration in vivo can serve as potential indicators for the diagnosis of several diseases such as pheochromocytoma and paraganglioma. Thus, the accurate quantification of CAs and their metabolites in biological samples is quite important and has attracted great research interest. However, due to their extremely low concentrations and numerous co-existing biological interferences, direct analysis of these endogenous compounds often suffers from severe difficulties. Employing suitable sample preparation techniques before instrument detection to enrich the target analytes and remove the interferences is a practicable and straightforward approach. To date, many sample preparation techniques such as solid-phase extraction (SPE), and liquid-liquid extraction (LLE) have been utilized to extract CAs and their metabolites from various biological samples. More recently, several modern techniques such as solid-phase microextraction (SPME), liquid-liquid microextraction (LLME), dispersive solid-phase extraction (DSPE), and chemical derivatizations have also been used with certain advanced features of automation and miniaturization. There are no review articles with the emphasis on sample preparations for the determination of catecholamine neurotransmitters in biological samples. Thus, this review aims to summarize recent progress and advances from 2015 to 2021, with emphasis on the sample preparation techniques combined with separation-based detection methods such capillary electrophoresis (CE) or liquid chromatography (LC) with various detectors. The current review manuscript would be helpful for the researchers with their research interests in diagnostic analysis and biological systems to choose suitable sample pretreatment and detection methods.