Magnetic quantitative analysis for multiplex glycoprotein with polymer-based elemental tags

Abstract

Carbohydrate biomolecules are difficult targets for analysis due to their branched structure and diverse modifications of saccharidic monomers. The variety of biochemical functions of carbohydrate biomolecules have attracted great and extensive attention, which has spurred a pressing need for rapid development of analytical methods for absolute quantification of glycoproteins in recent years. Herein a sensitive and selective method using magnetic separation coupled with inductively coupled plasma mass spectrometry (ICP-MS) detection is proposed for simultaneous determination of multiple glycoproteins. Haptoglobin (HP), hemopexin (HPX) and ovalbumin (OVA) were selected as target glycoproteins. They were firstly selected by lectin conjugated magnetic particles due to the glycol-structure, and then immunoreacted with antibodies labeled with Cd, Hg, Pb through poly(acrylic acid), respectively. The metal ions, corresponding to the concentration of glycoproteins, were released from antibody with an acid-dissolution step and subjected to subsequent ICP-MS detection. With consumption of only 50 μL sample solution, the established method presents a limit of detection of 0.032, 0.027 and 0.13 ng mL⁻¹ for HP, HPX and OVA, with the relative standard deviation of 7.4%, 6.8% and 7.6% (c = 5 ng mL⁻¹, n = 7), respectively. The response of magnetic immuno-ICP-MS assay for HP, HPX and OVA was linear over a dynamic range of 0.1–100 ng mL⁻¹, 0.1–100 ng mL⁻¹ and 0.5–100 ng mL⁻¹, respectively. The recoveries for HP, HPX and OVA in spiked human serum samples are in the range of 97.6–105%. The developed method is demonstrated to be versatile to multiple glycoproteins quantification in complicated samples.