A novel approach for the determination of exchangeable copper in serum using protein precipitation

Abstract

Copper (Cu) is an essential trace element with tightly regulated homeostasis in the body. Alterations in homeostasis may have severe consequences for human health. Diagnosis of Cu dyshomeostasis by assessment...

A fluorometric assay to determine labile copper(II) ions in serum

“…In addition to indirect quantification of loosely bound or non-CP-bound Cu 2+ in serum by determination of CP content and total Cu 2+ content 15 , 17 , 18 , several experimental approaches for direct measurement of this Cu 2+ species have been developed to date. This Cu 2+ pool, which is also often defined as extractable or exchangeable Cu 2+ , has been either directly quantified by liquid chromatography (LC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) 19 , 20 , or after extracting the loosely bound metal in serum with Cu 2+ chelators such as EDTA 9 , 21 or Cu 2+ -affine resins 22 , 23 followed by size ultrafiltration or size exclusion chromatography (SEC) and quantified either by ICP-MS 21 – 23 , atomic absorption spectrometry (AAS) 9 , 23 , or fluorescent Cu 2+ sensors 13 . The resulting concentration of loosely bound Cu 2+ was in the range of 0.5–7 µM 9 , 13 , 19 – 23 .…”

Sialic Acid-Functionalized Gold Nanoparticles for Sensitive and Selective Colorimetric Determination of Serotonin

“…Protein precipitation with organic solvents is a common sample cleanup technique in bioanalysis. 66 We tried using acetonitrile as an organic solvent to precipitate the proteins, but even though we obtained a clear supernatant after centrifugation, the recovery of the plasma aliquots was still low. To eliminate proteins and other endogenous cellular components such as phospholipids from the plasma, we prepared a ZrO 2 /SiO 2 column.…”

“…This was probably due to the absence of the nonspecific adsorption of proteins onto the SA-AuNPs. Protein precipitation with organic solvents is a common sample cleanup technique in bioanalysis . We tried using acetonitrile as an organic solvent to precipitate the proteins, but even though we obtained a clear supernatant after centrifugation, the recovery of the plasma aliquots was still low.…”

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…the labile fraction not bound to ceruloplasmin). 78 To 50 μL of serum were added 50 μL of 5 g L −1 EDTA solution then, after standing for 1 h, 100 μL of ACN at −20 °C was carefully layered on top. After vortexing for 10 s, the suspension was centrifuged for 10 min (20 000 g and 4 °C).…”