title: Transient isotachophoresis-capillary zone electrophoresis with contactless conductivity and ultraviolet detection for the analysis of paralytic shellfish toxins in mussel samples.
abstract: The accumulation of paralytic shellfish toxins (PSTs) in contaminated shellfish is a serious health risk making early detection important to improve shellfish safety and biotoxin management. Capillary electrophoresis (CE) has been proven as a high resolution separation technique compatible with miniaturization, making it an attractive choice in the development of portable instrumentation for early, on-site detection of PSTs. In this work, capillary zone electrophoresis (CZE) with capacitively coupled contactless conductivity detector (C(4)D) and UV detection were examined with counter-flow transient isotachophoresis (tITP) to improve the sensitivity and deal with the high conductivity sample matrix. The high sodium concentration in the sample was used as the leading ion while l-alanine was used as the terminating electrolyte (TE) and background electrolyte (BGE) in which the toxins were separated. Careful optimization of the injected sample volume and duration of the counter-flow resulted in limit of detections (LODs) ranging from 74.2 to 1020 ng/mL for tITP-CZE-C(4)D and 141 to 461 ng/mL for tITP-CZE-UV, an 8-97 fold reduction compared to conventional CZE. The LODs were adequate for the analysis of PSTs in shellfish samples close to the regulatory limit. Intra-day and inter-day repeatability values (percentage relative standard deviation, n=3) of tITP-CZE-C(4)D and tITP-CZE-UV methods for both migration time and peak height were in the range of 0.82-11% and 0.76-10%, respectively. The developed method was applied to the analysis of a contaminated mussel sample and validated against an Association of Official Analytical Chemists (AOAC)-approved method for PSTs analysis by high performance liquid chromatography (HPLC) with fluorescence detection (FLD) after pre-column oxidation of the sample. The method presented has potential for incorporation in to field-deployable devices for the early detection of PSTs on-site.
authors.affiliation: Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, GPO Box 252-75, Hobart, Tasmania 7001, Australia; Australian Centre for Research on Separation Science, Pharmacy School of Medicine, University of Tasmania, GPO Box 252-26, Hobart, Tasmania 7001, Australia; Institute for Marine and Antarctic Studies, University of Tasmania, Locked Bag 1370, 7250 Launceston, Tasmania, Australia; Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia.
authors.forename: Aemi S
authors.initials: AS
authors.lastname: Abdul Keyon
authors.affiliation: Australian Centre for Research on Separation Science, Pharmacy School of Medicine, University of Tasmania, GPO Box 252-26, Hobart, Tasmania 7001, Australia.
authors.forename: Rosanne M
authors.initials: RM
authors.lastname: Guijt
authors.affiliation: Institute for Marine and Antarctic Studies, University of Tasmania, Locked Bag 1370, 7250 Launceston, Tasmania, Australia.
authors.forename: Christopher J S
authors.initials: CJ
authors.lastname: Bolch
authors.affiliation: Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, GPO Box 252-75, Hobart, Tasmania 7001, Australia. Electronic address: mcb@utas.edu.au.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Breadmore
mesh_terms: D000409:Alanine; D000818:Animals; D049872:Bivalvia / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004573:Electrolytes; D019075:Electrophoresis, Capillary / Q000379:methods; D057625:Isotachophoresis / Q000379:methods; D008978:Mollusk Venoms / Q000032:analysis*; D012758:Shellfish / Q000032:analysis*
chemical_list: D004573:Electrolytes; D008978:Mollusk Venoms; D000409:Alanine
keywords: Capacitively coupled contactless conductivity detector; Capillary electrophoresis; Paralytic shellfish toxins; Transient isotachophoresis