CE‐MS with electrokinetic supercharging and application to determination of neurotransmitters

Abstract

Electrokinetic supercharging (EKS) is known as one of the most effective online electrophoretic preconcentration techniques, though pairing with it with mass spectrometry has presented challenges. Here, EKS is successfully paired with ESI‐MS/MS to provide a sensitive and robust method for analysis of biogenic amines in biological samples. Injection parameters including electric field strength and the buffer compositions used for the separation and focusing were investigated to achieve suitable resolution, high sensitivity, and compatibility with ESI‐MS. Using EKS, the sensitivity of the method was improved 5000‐fold compared to a conventional hydrodynamic injection with CZE. The separation allowed for baseline resolution of several neurotransmitters within 16 min with LODs down to 10 pM. This method was applied to targeted analysis of seven biogenic amines from rat brain stem and whole Drosophila tissue. This is the first method to use EKS with CE‐ESI‐MS/MS to analyze biological samples.

Recent developments in capillary and microchip electroseparations of peptides (2019–mid 2021)

“…Special reviews and articles deal with the particular sample clean-up techniques, such as online SPE with a nanoliter valve for analysis of opioid and Aβ peptide biomarkers in standards and plasma samples [64], two-dimensional affinity capture and separation platform for the isolation and enrichment of biopeptides and other biomarkers, potentially applicable for analysis of liquid biopsies [65], in-capillary immunopreconcentration with circulating biofunctionalized magnetic beads [66], and online electro-driven sample-stacking techniques [67]. The latter electro-driven procedures comprise field-amplified sample stacking [68], field-enhanced or field-amplified sample injection [68][69][70] large volume sample stacking [71], transient-ITP (t-ITP) [69,72], electrokinetic supercharging (EKS) [68,69], dynamic pH barrage junction and pH-mediated stacking [73], and electromembrane extraction [74].…”

CE‐MS for metabolomics: Developments and applications in the period 2018–2020

“…Wells et al developed a MS‐compatible electrokinetic supercharging (EKS) strategy for the sensitive and robust analysis of biogenic amines in biological samples [32]. This work utilized a low pH BGE that consists of 50 mM ammonium formate (pH 2.5) and 40% methanol, and a leading electrolyte (LE) that contained 250 mM ammonium formate (pH 2.5).…”

A Hypothesis From Metabolomics Analysis of Diabetic Retinopathy: Arginine-Creatine Metabolic Pathway May Be a New Treatment Strategy for Diabetic Retinopathy

“…Mass spectrometry is an analytical method that measures the ion-to-mass ratio based on the ionization of components in the samples by an ion source, and is widely used in the detection of metabolites ( 54 – 56 ). The sample can be directly analyzed by mass spectrometry, or in tandem with other separation methods to obtain mass spectra, such as liquid chromatography (LC) ( 57 – 59 ), gas chromatography (GC) ( 60 , 61 ), hydrophilic interaction chromatography-mass spectrometry (HILIC-MS) ( 62 ), Flow-injection analysis-mass spectrometry(FIA–MS) ( 63 ), or capillary electrophoresis (CE) ( 64 , 65 ). It should be noted that no single method can separate all metabolites simultaneously, as some metabolites are difficult to ionize, and in some cases, mass number limitations prevent mass spectrometry techniques from measuring all metabolites ( 66 ).…”