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Microchip analysis of lithium in blood using moving boundary electrophoresis and zone electrophoresis
Author(s) -
Vrouwe Elwin X.,
Luttge Regina,
Olthuis Wouter,
van den Berg Albert
Publication year - 2005
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200500012
Subject(s) - capillary electrophoresis , electrophoresis , lithium (medication) , chromatography , analytical chemistry (journal) , detection limit , chemistry , dispersion (optics) , matrix (chemical analysis) , spark plug , materials science , optics , engineering , aerospace engineering , medicine , physics , endocrinology
Abstract The determination of inorganic cations in blood plasma is demonstrated using a combination of moving boundary electrophoresis (MBE) and zone electrophoresis. The sample loading performed under MBE conditions is studied with the focus on the quantitative analysis of lithium. A concentration adjustment takes place when the sample components migrate into the chip during the sample loading step. Using a heart‐cutting method, a diluted sample plug is subsequently separated with capillary zone electrophoresis. The excessive dispersion that is typical of the samples with a high ionic strength is thereby prevented. The method can be easily applied to commercially available capillary electrophoresis microchips under the condition that the electroosmotic flow is suppressed. For the first time the lithium concentration is determined in the blood plasma from a patient on lithium therapy without sample pretreatment. Using a microchip with conductivity detection, a detection limit of 0.1 mmol/L is obtained for lithium in a 140 mmol/L sodium matrix.