Parametric analysis of wax printing technique for fabricating microfluidic paper-based analytic devices (µPAD) for milk adulteration analysis
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Accurate prediction of hydrophobic–hydrophilic channel barriers is essential in the fabrication of paper-based microfluidic devices. This research presents a detailed parametric analysis of wax printing technique for fabricating µPADs. Utilizing commonly used Grade 1 filter paper, experimental results show that the wax spreading in the paper porous structure depends on the initially deposited wax line thickness, a threshold melting temperature and melting time. Initial width of the printed line has a linear relationship with the final width of the barrier; however, a less pronounced effect of temperature was observed. Based on the spreading behavior of the molten wax at different parameters, a generalized regression model has been developed and validated experimentally. The developed model accurately predicts wax spreading in Whatman filter paper: a non-uniform distribution of pores and fibers. Finally, tests were carried out for calorimetric detection of commonly used adulterants present in milk samples.
KeywordsPaper based Microfluidics Fabrication Wax printing Analytical devices Milk adulterants
List of symbols
Average wax spreading from the edges of printed line
Final hydrophilic channel width
Width of printed line
Initial hydrophilic channel width
Electronic supplementary information
We thank our lab colleagues Nauman Khan and Zia-ur-Rehman for their handful of suggestions during the lab work.
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Compliance with ethical standards
Conflict of interest
The authors declare that there is no conflict of interests regarding the publication of this paper.
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