Preparation of Ti4+-immobilized modified silica capillary trapping column for on-line selective enrichment of phosphopeptides

In this work, we have developed Ti4+-immobilized capillary trapping column (250 pm i.d.) for highly specific on-line enrichment of phosphopeptides in the bio-samples. It minimizes the sample loss and improves the effectiveness of phosphopeptide detection that the limit of detection is as low as 1 fmol/mu L. It is successfully applied to the detection of phosphopeptides from complex biological samples, such as skim milk, human serum and mouse brain. The results indicate that the Ti4+-immobilized capillary trapping column is time-effective and has the great potential of application in low-abundance phosphopeptides on-line analysis. The prepared Ti4+-immobilized capillary trapping column will be further used in LC/MS platform for phosphoproteome analysis. (C) 2016 Elsevier B.V. All rights reserved.