title: Simplified microchip electrophoresis for rapid separation of urine proteins.
abstract: BACKGROUND
  Urine protein test has been widely used in clinics, but to determine the type of proteinuria is usually difficult due to technical limitations.
  
  
  METHODS
  In the current study, a rapid and simple method to separate and determine urine proteins by a microchip electrophoresis (ME) system has been developed in which only 4 min are required.
  
  
  RESULTS
  Optimal separation conditions have been established by using 15 s injection time at 500 and 1,500 V separation voltage in 75 mmol/l borate buffer containing 0.8 mmol/l calcium lactate and 1% ϕ ethylamine (pH 10.55). Relative standard deviation (RSD) of migration time with purified human albumin and human transferring was 2.68% and 2.24%, and RSD of the peak area was 5.85% and 4.96%, respectively. The linear detection range was 1.0-15.0 g/l for purified human albumin and 1.0-10.0 g/l for human transferrin, with the same detection limit (S/N = 3) of 0.4 g/l. Finally, comparing to conventional agarose gel electrophoresis, the same results were obtained by using ME by testing clinical samples including 60 selective proteinuria, 105 nonselective proteinuria, and 6 overflow proteinuria.
  
  
  CONCLUSIONS
  This newly established ME could have broad applications to determine the type of proteinuria in clinics.
authors.affiliation: Medical Laboratory Center, Affiliated Hospital of Nantong University, Jiangsu Province, P.R China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Song
authors.forename: Huimin
authors.initials: H
authors.lastname: Wang
authors.forename: Saoqing
authors.initials: S
authors.lastname: Ju
authors.forename: Qinghui
authors.initials: Q
authors.lastname: Jin
authors.forename: Chunping
authors.initials: C
authors.lastname: Jia
authors.forename: Hui
authors.initials: H
authors.lastname: Cong
mesh_terms: D002021:Buffers; D017610:Calcium Compounds / Q000737:chemistry; D004560:Electricity; D046209:Electrophoresis, Microchip / Q000379:methods*; D005021:Ethylamines / Q000737:chemistry; D006801:Humans; D007773:Lactates / Q000737:chemistry; D057230:Limit of Detection; D011506:Proteins / Q000302:isolation & purification*; D011507:Proteinuria / Q000175:diagnosis*; D012044:Regression Analysis; D015203:Reproducibility of Results; D012996:Solutions; D013997:Time Factors; D014556:Urine / Q000737:chemistry*
chemical_list: D002021:Buffers; D017610:Calcium Compounds; D005021:Ethylamines; D007773:Lactates; D011506:Proteins; D012996:Solutions; C110051:calcium lactate; C041564:ethylamine
keywords: UV detection; calcium lactate; ethylamine; microfluidic chip electrophoresis; selectivity of proteinuria; urine proteins