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2‐D t‐ITP/CZE determination of clinical urinary proteins using a microfluidic‐chip capillary electrophoresis device
Author(s) -
Wu Ruige,
Yeung William S. B.,
Fung YingSing
Publication year - 2011
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.201100214
Subject(s) - chromatography , capillary electrophoresis , analyte , isotachophoresis , immunoassay , chemistry , detection limit , microfluidics , capillary action , sample preparation , analytical chemistry (journal) , materials science , antibody , nanotechnology , electrode , immunology , electrolyte , composite material , biology
To replace the time‐consuming sample pretreatment procedure, a microfluidic chip‐CE device incorporating on‐chip sample desalting/preconcentration with transient isotachophoresis (ITP)/capillary zone electrophoresis (CZE) was fabricated to perform sequential on‐chip sample pretreatment and CE determination of four urinary proteins in clinical samples. On‐chip sample desalting, clean‐up and analyte preconcentration enable removing interfering sample matrix prior to transferring analytes to separation capillary for transient ITP/CZE determination. Four important urinary proteins transferrin, β2‐microglobulin, human serum albumin (HSA) and immunoglobulin G (IgG), investigated were shown to achieve quantitation limits sufficiently high to meet medical requirements, sensitivity enhancement up to 40‐fold and detection limits down to 0.3, 0.05, 0.6, 0.5 mg/L, respectively. Compared to the stacking effect, the use of a large sample size was found to be the major factor for sensitivity enhancement. The method reliability is established by close to 100% recoveries and statistical agreement of results from the method developed with currently used clinical radio‐immunoassay method for all four proteins investigated. Moreover, an assay time of less than 10 min is needed in the method developed as compared to 7 h for the radio‐immunoassay method.