Evaluation of different operating modes of an autosampler for portable capillary electrophoresis.

A compact, inexpensive sampler instrument for portable capillary electrophoresis (CE) was developed and tested to monitor common inorganic ions in drinking water samples. The sampler uses peristaltic and vacuum pumps and pinch and check valves to control liquid flows. The paper also addresses various aspects of CE associated with portability, open access instrumentation and prospects of CE for citizen science. The extensive use of items provided by the electronic and computer industry contributes to this trend.

Autosampler for portable capillary electrophoresis.

A compact, inexpensive sampler instrument for portable capillary electrophoresis was developed for monitoring illegal drugs in human body fluids and evaluated for γ-hydroxybutyric acid (GHB) in simulated saliva samples. The sampler uses peristaltic pumps and pinch and check valves to activate liquid flows. This short communication addresses aspects of CE associated with portability, open access instrumentation, and prospects of CE for citizen science. The extensive use of items provided by the electronic and computer industry contributes to this trend.

The influence of organic solvents on phenylethylamines in capillary zone electrophoresis.

The aim of this study was to investigate the influence of organic solvents on the electrophoretic separation of phenylethylamines. The background electrolyte composition was adjusted with different protic (methanol, ethanol, and 2-propanol) and aprotic (dimethyl sulfoxide and acetonitrile) solvents. Two groups of analytes were studied. The first group contained phenylethylamines with an amine group only, DL-1-phenylethylamine and amphetamine. The second group represented phenylethylamines with both amine and phenolic hydroxyl groups, dopamine and tyramine. Experiments revealed no or minor influence of the organic modifiers on the electromigration behavior of the analytes from the first group (containing only the amine group) and a drastic effect on the second group (containing the additional phenolic hydroxyl group). Dopamine and tyramine showed various electrostatic, hydrophobic, and hydrogen-bonding interactions with both protic and aprotic organic solvents. The dependence of the electrophoretic mobility of dopamine and tyramine on the concentration of the organic solvents provided direct evidence of the formation of hydrogen bonds between dopamine or tyramine and the organic solvent. The baseline separation was achieved by the addition of at least 20% v/v of organic solvent (protic or aprotic) to the background electrolyte. The analyte migration time repeatabilities were within 0.7-4.1% for absolute and 0.2-1.9% for normalised migration times. The proposed bonding mechanism and behavior of phenylethylamines were examined and confirmed by NMR spectroscopy.

Portable fully automated oral fluid extraction device for illegal drugs.

Currently used methods for in-field determination of illegal drugs involve various test kits based mainly on the immunoassay technique, where the presence of a compound of interest is assessed by antibody-antigen reaction and manifested by observable color change. Despite being accepted and widely used by police forces to test the presence of illegal drugs in a suspect person, these tests often suffer from unreliable results (high level of false-positive and/or false-negative) due to the cross-reactivity and difficulties with quantification. Therefore, we have developed a portable capillary electrophoresis instrument to determine illegal drugs in oral fluid collected from a suspected person. However, this drug analyzer has still required manual sample preparation. Therefore, this research aimed to develop, test, and validate a fully automated sample pretreatment (purification, extraction, pre-concentration) prototype compatible with the capillary electrophoresis drug of abuse analyzer and suitable for confirmatory analysis by mass spectrometry. The cotton swab from Salivette® oral fluid collector was examined and integrated into the fully automated extractor prototype. The recoveries for the automated extractor were between 18 and 20%, with repeatabilities within 5-11% for 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), cocaine (COC), and cocaethylene (COET). The developed extraction device was easy to use even for unskilled persons, required minimal liquid handling, and was applicable to use in field conditions.

Capillary Electrophoresis as a Monitoring Tool for Flow Composition Determination.

Flow analysis is the science of performing quantitative analytical chemistry in flowing streams. Because of its efficiency and speed of analysis, capillary electrophoresis (CE) is a prospective method for the monitoring of a flow composition withdrawn from various processes (e.g., occurring in bioreactors, fermentations, enzymatic assays, and microdialysis samples). However, interfacing CE to a various flow of interest requires further study. In this paper, several ingenious approaches on interfacing flow from various chemical or bioprocesses to a capillary electrophoresis instrument are reviewed. Most of these interfaces can be described as computer-controlled autosamplers. Even though most of the described interfaces waste too many samples, many interesting and important applications of the devices are reported. However, the lack of commercially available devices prevents the wide application of CE for flow analysis. On the contrary, this fact opens up a potential avenue for future research in the field of flow sampling by CE.

Use of a newly-developed portable capillary electrophoresis analyser to detect drugs of abuse in oral fluid: A case study.

The aim of the current study was to develop and validate an analytical method to determine whether drugs of abuse (DOA) were present in oral fluid (OF) using a newly-developed, portable capillary electrophoresis (CE) instrument coupled to a deep ultra-violet fluorescence detector (FD). The performance of this portable CE-FD DOA analyser was tested at the Weekend Festival Baltic (Pärnu, Estonia) between 2016 and 2018 as well as on the roadside OF samples collected by the police. The study reported 128 analysed cases in which persons were allegedly found to have been under the influence of DOA. The samples were analysed for amphetamine (AMP), methamphetamine (METH), 3,4-methylenedioxy-methamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), cocaine (COC) and cocaethylene (COET). Subsequent toxicological reports revealed that 26% cases were negative, and 74% were positive. The most frequently detected and quantified DOA was MDMA (68 cases, 62%). A comparative study was conducted to validate the accuracy of using the CE-FD DOA analyser versus classic high-performance liquid chromatography coupled to mass spectrometry (HPLC-ESI-MS). Diagnostic statistics for CE-FD DOA were also evaluated and were higher than 99.5%. In addition, all zeta-scores were lower than 2 when both methods were compared, showing that the CE-FD analyser can be implemented as a reliable, sensitive and convenient tool for roadside and workplace testing for DOA.

Rapid and sensitive capillary electrophoresis method for the analysis of Ecstasy in an oral fluid.

In the present study, a capillary electrophoresis method, with a native fluorescence detection for the quantification of three amphetamine derivatives, methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-methamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA) in an oral fluid is described. The reported CE method has made it possible to assess Ecstasy abuse in approximately 15 min, including a saliva sample collection, pretreatment procedures and capillary electrophoresis (CE) analysis. The proof of the principle that was demonstrated on a home-made lab scale instrument has had the potential to be easily translated onto a truly portable instrument for on-site measurements. The baseline CE separation of the three illegal drugs was achieved in 10 min, by applying an aqueous background electrolyte (BGE) that was composed of 40 mM phosphoric acid and 10 mM triethanolamine. The amphetamine derivatives were detected at their λex/λem maximum (280/326 nm) with LOD values of about 3 ng/mL for each amphetamine. The recovery of the compounds from the collection pad was about 40% of the LOQ concentrations and the inter-day precision was less than 6% for all of the analytes. The procedure was applied to a quantitation of oral fluid (OF) samples that were collected during the Baltic Weekend Music Festival that was held in Estonia.

In Situ Determination of Illegal Drugs in Oral Fluid by Portable Capillary Electrophoresis with Deep UV Excited Fluorescence Detection.

The present study demonstrates the potential of a portable capillary electrophoresis (CE) instrument, coupled to deep UV fluorescence detector (FD) with a 230-255 nm excitation wavelength range, for the determination of the abuse of illegal drugs in oral fluids in situ. CE was introduced in this study due its exceptional power of separation and resolution, short analysis time, and ability for miniaturization for on-site assessment of different substances. The deep UV fluorescence detector was equipped with five interchangeable emission filters, in the emission wavelength range from 278 to 600 nm, and was successfully employed for determination of natively fluorescing illegal drugs, such as cocaine, cocaethylene, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxeamphetamine (MDA), 3,4-methylenedioxy- N-ethylamphetamine (MDEA), para-methoxyamphetamine (PMA), para-methoxy- N-methylamphetamine (PMMA), amphetamine (AMP), methamphetamine (METH), tetrahydrocannabinol (THC) and cannabidiol (CBD). The developed FD showed impressive sensitivity. The instrumental detection limit was 0.5 µg/L for MDMA. It also showed broad linearity, up to 50 mg/L for MDMA. The noise CV% was 1.1% for an empty capillary and 0.6% for a capillary filled with acetonitrile. The portable CE-FD with developed electrophoretic methodologies was successfully utilized for the determination of illegal abuse of drugs during "Weekend" 2016 and 2017 Music Festivals (Estonia). Moreover, CE-FD can be employed for detection of other natively fluorescing compounds in the proposed range (e.g., for different phenolic compounds, BTEX, naphthalene derivatives, and others), significantly widening the applicability of developed CE-FD instrument.