Sensitive, direct procedures for simultaneous determinations of iron and copper in serum, with use of 2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol (nitro-PAPS) as ligand.
We developed a direct, simple, and sensitive procedure for the simultaneous colorimetric assay of iron and copper in serum, using sodium dodecyl sulfate-ascorbic acid to dissociate iron and copper from transferrin and ceruloplasmin, respectively. We also use a new water-soluble reagent, 2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol disodium salt (nitro-PAPS) and thioglycolic acid to eliminate interference from copper in the measurement of iron. Within- and between-run precisions of the present method were 2.5-2.8% for iron and 1.8-4.6% for copper. The proposed method is susceptible to interference by hemoglobin and lipemia, especially for the iron assay. Linear-regression analyses of results of the proposed method with those of the bathophenanthroline method for iron and of the atomic absorption spectroscopic method for copper correlated well (r = 0.996, Sy/x = 0.73 and r = 0.959, Sy/x = 1.11, respectively).
Yamashita
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Department of Clinical Laboratory, Gifu University Hospital, Japan.
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D001391:Azo Compounds; D002863:Chromogenic Compounds; D003124:Colorimetry / Q000379:methods* / Q000706:statistics & numerical data; D003300:Copper / Q000097:blood*; D006454:Hemoglobins; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000097:blood*; D007700:Kinetics; D008055:Lipids / Q000097:blood; D011786:Quality Control; D013053:Spectrophotometry
D001391:Azo Compounds; D002863:Chromogenic Compounds; D006454:Hemoglobins; D008055:Lipids; C055388:2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol; D003300:Copper; D007501:Iron