Determination of copper in plasma ultrafiltrate by atomic-absorption spectrophotometry using carbon furnace atomisation

Abstract

A method for the direct determination of the level of copper in plasma ultrafiltrate using atomic-absorption spectrometry with carbon furnace atomisation is reported. The relative standard deviation and the detection limit expressed as 26 were 3.6% (50 pl of 0.05 p g ml-l copper solution) and 0.0036 p g ml-l, respectively. Interferences from the salt matrix, the use of background correction and the problems of contamination caused by the low level of copper are discussed. The method has been applied to the determination of the level of copper in the plasma ultrafiltrate of patients with rheumatoid arthritis.

Copper distribution and reactivity in serum following administration of cuprous oxide to rats and guinea pigs

“…Cuprous oxide was administered as a suspension in a 5% mulgofen (EL 719 GAF Co., Manchester, England) suspension in distilled water (0.2 ml/100 g body weight). Total serum copper analysis was by atomic absorption spectrometry using carbon furnace atomization [4]. Albuminassociated copper concentrations were determined by separating the proteins by electrophoresis on cellulose acetate strips, excising the albumin fraction and inserting the solid strip into the furnace [5,6] Cellulose acetate was preferred to polyacrylamide gels since the strips were thinner and gave rise to less smoke during ashing and atomization.…”

“…cut off < 1000) analysis for copper was also by atomic absorption. Interference from chloride ions in the ultrafiltrate is a problem with this technique of analysis and the method used to overcome this has been described previously [4]. Caeruloplasmin oxidase activity was estimated by the method of BOIANO et al [7] and sulphydryl group activity by the method of ELLMAN [8].…”

Total serum copper and ceruloplasmin levels following administration of copper aspirinate to rats and guinea-pigs

“…These methods were rigorously applied in each case. Relative standard deviation and detection limits [6,7] indicate that the procedures are adequate for the determination of copper at the concentration found in this study. Ceruloplasmin oxidase activity [8] and free thiol concentration ]9] were estimated using established methods.…”

“…Ultrafiltration was carried out under nitrogen, using 25 mm Millipore (PSAC) membranes with a nominal mass cut-off about 1000. Electrophoresis of serum was on cellulose acetate strips (BDH OXOID) at pH 8.6 in a barbitone buffer with an 8 cm bridge for 75 m at 180 V. Methods for the prevention of contamination of the sample have been described previously for each determination [6][7][8]. These methods were rigorously applied in each case.…”

“…Total serum copper [6], ultrafilterable copper [6] and copper levels in separated serum protein fractions [7] were estimated by methods previously described, using atomic absorption spectroscopy with carbon furnace atomization. Ultrafiltration was carried out under nitrogen, using 25 mm Millipore (PSAC) membranes with a nominal mass cut-off about 1000.…”