Current Sample Preparation Methodologies for Determination of Catecholamines and Their Metabolites

Abstract

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.

Keywords: catecholamines; chemical derivatization; chromatography; sample preparation.

Figure 1

The analysis process for the determination of CAs and their metabolites.

Figure 2

Synthesis mechanism and extraction of CAs by Fe₃O₄@PTA@MIL-100(Fe)-B [48].

Figure 3

Determination of free biogenic monoamines and their metabolites in urine using thin-film solid-phase microextraction [61].

Figure 4

Schematic diagram of the online micro-solid-phase extraction system, reprinted from [70,71]. (A) The in-situ polymerization of monolithic column (a), schematic diagram of the online micro-solid-phase extraction system coupled to HPLC (b). (B) Schematic procedures showing on-line preconcentration and separation. (a) Sample injection; (b) focusing; and (c) separation.

Figure 5

Magnetic borate-modified MXene composite for the extraction of CAs [74].

Figure 6

(A) HPLC-UV chromatograms (a), elution from B-hDIPs-SPE spiked with 0.5 μg mL⁻¹ (b), spiked with 1.0 μg mL⁻¹ (c), spiked with 2.0 μg mL⁻¹ (d). Peaks: (1) norepinephrine, (2) epinephrine, (3) dopamine. HPLC conditions were: a Thermo scientific C18 column (250 mm × 4.6 mm, 5 mm) and UV detector at 280 nm, mobile phase, MeOH-NaH₂PO₄ (20 mmol L⁻¹, pH 4.0) (5:95, v/v) with flow rate at 0.5 mL min⁻¹ with injection volume 10 μL. Reproduced with permission from Reference [8]. (B) Typical chromatogram of derivatives of the six selected catecholamines and related compounds. Mobile phase: methanol and 20 mM pH 3.5 H₃Cit–Na₂HPO₄ buffer. Detection: fluorescence (490/510 nm). Flow rate: 0.7 mL/min. Injection volume: 20 μL. Concentration: 0.05 μM each (L-DOPA concentration: 0.1 μM). Peaks: (1) L-DOPA; (2) Tyr; (3) NE; (4) E; (5) DA; (6) MN and (a) TMBB-Su hydrolyzate. Reproduced with permission from Reference [81]. (C) Extracted ion chromatogram of ten targeted analytes. Selected reaction monitoring (SRM) was used to detect targeted analytes. Chromatographic conditions: column, Acquity UPLC BEH C18 column (2.1 mm × 150 mm, 1.7 μm particle size) with VanGuard pre-column; flow rate = 0.3 mL/min; column temperature 30 °C. peaks: Glu—glutamic acid, GABA—γ-aminobutyric acid, HIS—histamine, 5-HIAA—5-hydroxyindoleacetic acid, HVA—homovanilic acid, SER—5-hydroxytryptamine, DOPAC—3,4-dihydroxyphenylacetic acid, NADR—noradrenaline, ADR—adrenaline, DA—dopamine. Reproduced with permission from Reference [23].

Figure 7

Label-free silver triangular nanoplates for spectrophotometric determination of catecholamines and their metabolites [96].