Total α1-acid glycoprotein determination in serum samples using disposable screen-printed electrodes and osmium (VI) as electrochemical tag.

Alpha-1-acid glycoprotein (AGP) or Orosomucoid is a serum glycoprotein which belongs to the group of acute phase proteins. It is a potential biomarker for inflammatory bowel diseases. In this sense, there is a need for developing fast and cheap analytical methods for diagnosis, prognosis and follow-up of these diseases. In this work, we propose a simple and cheap electrochemical method for total AGP determination using disposable carbon screen-printed electrodes (SPE) and using a selective acidic precipitation of the rest of proteins. This method avoids the use of biological components, decreasing dramatically the analysis cost. Firstly, AGP is labeled with an electrochemical tag (osmium (VI) complex) and then the total amount of AGP is quantified by adsorptive transfer stripping square wave voltammetry. The method optimized showed a good linear correlation (r = 0.9992) and limit of detection of 1.6mgl-1. The methodology was successfully applied to quantify AGP in a commercial serum sample. This methodology could be useful in clinical diagnosis because of AGP levels increase two or three times when inflammatory processes happen. Moreover, the inherent advantages of SPE technology (low sample consumption, low cost and point of care testing) make this methodology very attractive in this field.