Inductively coupled plasma mass spectrometry for determination of total urinary protein with CdTequantum dots label

Abstract

In the present work, a novel methodology for sensitive quantification of human total urinary protein by using CdTe quantum dots label and inductively coupled plasma mass spectrometry (ICP-MS) was developed. It combined the intrinsically high sensitivity of elemental mass spectrometric analysis with the remarkable quantity of metallic ions from the nanoparticles label. Through the direct conjugation of CdTe quantum dots and proteins, the ICP-MS signal intensity of cadmium is proportional to the concentration of proteins. The optimization of bio-conjugation parameters was investigated and discussed in detail. The proposed method featured a low detection limit (0.008 μg mL⁻¹ for HSA) and wide linear range response over 4 orders of magnitude. Moreover, there are very little interferences from common inorganic ions and other coexisting compounds. The developed method was successfully applied for detecting total protein in 50 human urine samples and the results were in good agreement with those reported by the hospital, which indicated a great potential for routine clinical application.