One-Step Polylactic Acid Screen-Printing Microfluidic Paper-Based Analytical Device: Application for Simultaneous Detection of Nitrite and Nitrate in Food Samples

Abstract

In this work, we report a one-step approach for fabricating screened-printed microfluidic paper-based analytical devices (μPADs) using polylactic acid as a new hydrophobic material. A polylactic acid solution was screen printed onto chromatography papers to create hydrophobic patterns for fluidic channels. The optimal polylactic acid concentration for successful device fabrication is 9% w/v. The μPADs were fabricated within 2 min and provided high reproducibility and stability. The utility of polylactic acid screen-printing was demonstrated for the simultaneous detection of nitrite and nitrate using colorimetric detection. Under optimized experimental conditions, the detection limits and the linear ranges, respectively, were 1.2 mg L−1 and 2–10 mg L−1 for nitrite and 3.6 mg L−1 and 10–50 mg L−1 for nitrate. The detection times for both ions were found to be within 12 min. The developed μPAD was applied for the simultaneous determination of these ions in food samples, and no significant differences in the analytical results were observed compared to those of the reference method. The polylactic acid screen-printing approach presented here provides a simple, rapid, and cost-effective alternative fabrication method for fabricating μPADs.

A New Paper-Based Microfluidic Device for Improved Detection of Nitrate in Water

“…Different parameters that go into the production of Zinculose were discussed in detail in a previous article [ 38 ]. Previously, researchers used pipetting [ 33 , 34 , 35 ] or placing paper in a suspension [ 37 ] to deposit zinc microparticles on paper. The main drawback of these methods is the lack of reproducibly depositing the same amount of zinc microparticles in the device as these particles rapidly settle down in any water suspension.…”

“…Thus far, only five paper-based microfluidic devices have been developed for the detection of nitrate. These devices use the Griess assay for the colorimetric detection of nitrate in water [ 33 ], food samples [ 34 , 35 , 36 ], and human saliva [ 37 ]. Since the Griess assay is specific to nitrite, nitrate molecules have to be first reduced to nitrite before undergoing the reaction.…”

Microfluidic Paper-Based Analytical Devices for the Determination of Food Contaminants: Developments and Applications

“…Teepoo et al. presented a polylactic acid screen printing technology to create microfluidic channels to manufacture μPADs and detect nitrite and nitrate based on the Griess method . The color change of the detection area was determined by an image analysis program, and the concentration of nitrate and nitrite were inversely derived.…”

“…123 Teepoo et al presented a polylactic acid screen printing technology to create microfluidic channels to manufacture μPADs and detect nitrite and nitrate based on the Griess method. 124 The color change of the detection area was determined by an image analysis program, and the concentration of nitrate and nitrite were inversely derived. By optimizing the experimental conditions, the μPADs have successfully and accurately determined the nitrate and nitrite in five food samples: smoked sauce, chicken sauce, fish balls, meatballs, and sour pork.…”

Colorimetric Determination of Nitrate after Reduction to Nitrite in a Paper-Based Dip Strip

“…These devices can also provide qualitative or quantitative results and data at the point of care without the need for specialized equipment or power sources. Several paper-based devices have been developed for various applications, such as for water analysis [1][2][3][4], biomedical applications [5,6], food analysis [7][8][9][10], soil analysis [11] and many other miscellaneous applications [12][13][14][15]. The field of paper-based microfluidics is expected to continue garnering greater attention as more applications are sought after or the performance improved for the ones already developed [16].…”