Automated on-line packed fiber solid phase extraction for determination of urinary catecholamines

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.

Automated and semi-automated packed sorbent solid phase (micro) extraction methods for extraction of organic and inorganic pollutants

In this study, the packed sorbent solid phase (micro) extraction methods from manual to automated modes are reviewed. The automatic methods have several remarkable advantages such as high sample throughput, reproducibility, sensitivity, and extraction efficiency. These methods include solid-phase extraction, pipette tip micro-solid phase extraction, microextraction by packed sorbent, in-tip solid phase microextraction, in-tube solid phase microextraction, lab-on-a-chip, and lab-on-a-valve. The recent application of these methods for the extraction of organic and inorganic compounds are discussed. Also, the combination of novel technologies (3D printing and robotic platforms) with the (semi)automated methods are investigated as the future trend.

Electrospun Polycrown Ether Composite Nanofibers as an Adsorbent for On-Line Solid Phase Extraction of Eight Bisphenols from Drinking Water Samples with Column-Switching Prior to High Performance Liquid Chromatography

Bisphenols (BPs) are a class of endocrine disruptors widely existing in the environment. They have a great impact on human health owing to their environmental endocrine disrupting effects, chronic toxicity, neurotoxicity, cytotoxicity and genetic toxicity. In this paper, an on-line packed fiber solid phase extraction (PFSPE) coupling with column-switching HPLC-FLD determination method was developed for the determination of eight BPs in drinking water. The poly (dibenzo-18-crown-6-ether)/polystyrene composite nanofibers (PDB18C6/PS) were prepared by electrospinning and used as an adsorbent for the on-line PFSPE column. The on-line PFSPE-HPLC equipment contained a dual ternary pump and a switching valve to enable enrichment, purification, and analysis directly in the system. The results showed that the proposed on-line PFSPE-HPLC-FLD method realized the simultaneous separation and detection of eight BPs: BPF, BPE, BPA, BPB, BPAF, BPAP, BPC and BPZ. The curves of the target analytes were prepared with good correlation coefficient values (r2 > 0.998) in the range of 50−1000 pg/mL. The limit of detection (S/N = 3) was 20 pg/mL, the limit of quantitation (S/N = 10) is 50 pg/mL. The recoveries of eight BPs were 94.8−127.3%, and the intra-day precisions (RSD) were less than 10%. The PFSPE column made of the PDB18C6/PS composite nanofibers has stable properties and can be reused at least 200 times. In the detection of drinking water samples, BPZ was detected in nearly 80% of drinking water samples, and BPA, BPAP, BPF and BPAF were also detected in some water samples. This high level of integration and automation was achieved in pretreatment of eight BPs from water samples. The proposed simple, rapid, and practical method has been successfully applied to the detection of eight BPs in drinking water, which can provide powerful technical support for drinking water quality and safety monitoring.

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.

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.

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

UPLC-MS/MS methods are the gold standard for routine, high-throughput measurements of biogenic monoamines for the diagnosis of catecholamine-producing tumors. However, this cannot be achieved without employing efficient sample pretreatment methods. Therefore, two pretreatment methods, thin-film solid phase microextraction (TF-SPME) and packed fibers solid phase extraction (PFSPE), were developed and evaluated for the analysis of biogenic monoamines and their metabolites in urine. A hydrophilic-lipophilic balance (HLB) coating was chosen for the thin-film blade format SPME method and compared with a Polycrown ether (PCE) composite nanofiber used as an adsorbent for the PFSPE method. Under optimal conditions, the absolute extraction recovery and relative matrix effect of the newly developed TF-SPME method were determined to be 35.7-74.8% and 0.47-3.63%, respectively. The linearity was 0.25-500 ng mL^-1 for norepinephrine, epinephrine, dopamine, normetanephrine 3-methoxytyramine, serotonin, histamine, and 0.1-500 ng mL^-1 for metanephrine. The intra-and inter-assay coefficients of variation were 0.7-8.7%, and the respective accuracies were calculated to be 90.8-104.7% and 89.5-104.5% for TF-SPME. Compared with the PFSPE method, the TF-SPME method had a higher extraction efficiency, lower matrix effects and a wider linear range for eight target substances, which ensured higher accuracy of simultaneous detection of all compounds of interest. Therefore, the proposed TF-SPME method can be employed for the high throughput screening for neuroendocrine tumors in a routine clinical setting and other relative research by simultaneous quantitation of urine eight biological monoamines in a single run.