title: Isotachophoresis as a candidate reference method in analytical chemistry. Determination of sodium in serum.
abstract: Isotachophoresis seems a likely candidate for a reference method, as it is more accurate and precise than common routine methods. The response is highly linear and depends on a well defined transport number of the leading ion, stability of the driving current, mobility of the separand, which is well controlled by the leading electrolyte and the use of a high-resolution detector. The suitability of isotachophoresis as a reference method was investigated for the determination of sodium in human serum. The operational conditions were 0.01 M K+/citrate (leading electrolyte) at pH 5.5 and 0.01 M creatinine X HCl (terminating electrolyte). Both n-butylamine and ammediol could be used as internal standards. The calibration graph constructed from standard solutions, diluted by weight with the internal standard, yielded a correlation coefficient of 0.99994 (n = 50) in the working range. The method seems especially useful for the determination of any ionic solute in, e.g., clinical samples (lithium, calcium, creatinine or drugs).
mesh_terms: D002082:Butylamines; D004563:Electrochemistry; D004586:Electrophoresis; D006801:Humans; D011409:Propylene Glycols; D012015:Reference Standards; D012964:Sodium / Q000097:blood*; D012965:Sodium Chloride / Q000032:analysis
chemical_list: D002082:Butylamines; D011409:Propylene Glycols; D012965:Sodium Chloride; D012964:Sodium; C019250:2-amino-2-methyl-1,3-propandiol; C032462:n-butylamine