Design of a microfluidic paper-based device for the quantification of phenolic compounds in wine samples

In this work, the design and development of a microfluidic paper-based device (mu PAD) for the quantification of total phenolic compounds (TPC) in wines is described. The developed mu PAD was based upon the vertical flow concept and the colour reaction used was the known Folin-Ciocalteu reaction using gallic acid as reference phenolic compound. After studying operational parameters, namely type of paper, reagents and sample volume, a dynamic range of 5-50 mg L-1 was obtained with a limit of detection of 1.2 mg L-1. The described device proved to have good precision (relative standard deviation < 5%) and no significant interferences were observed from known compounds present in wines. Furthermore, the stability of the colour product and of the device itself were assessed; the mu PAD was stable for 30 days (in the dark at room temperature) and it could be scanned up to 8 h after sample introduction. The developed mu PAD pose as a simple method for TPC quantification and was successfully applied to several wine samples including sparkling and table wines with two different approaches: i) using gallic acid as reference compound with standard addition; and ii) using taniraisin with external cali-bration. The accuracy of the proposed mu PAD method was assessed by comparison with the reference spectro-photometric method according to the International Organisation of Vine and Wine (OIV) recommendations.

Automated summary

This paper describes the design and development of a microfluidic paper-based device for the quantification of total phenolic compounds in wines. The developed device showed good precision, stability, and no significant interferences from known compounds in wines.