Microfluidic Paper-based Analytical Device for the Determination of Hexavalent Chromium by Photolithographic Fabrication Using a Photomask Printed with 3D Printer

Asano, Hitoshi; Shiraishi, Yukihide

doi:10.2116/analsci.34.71

Cited by 36 publications

(12 citation statements)

References 32 publications

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“…They are fabricated by forming hydrophobic barriers in hydrophilic paper producing hydrophilic channels for liquid flow. 26 A number of fabrication techniques have been developed for μPADs including lamination, 27 wax printing, 28 inkjet printing, 29 photolithography 30,31 and flexographic printing. 32 The advantages of using μPADs over traditional detection platforms are that the paper is widely available at a low cost.…”

Section: Introductionmentioning

confidence: 99%

Paper-based DPPH Assay for Antioxidant Activity Analysis

2018

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We report on a paper-based 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) assay for a simple, inexpensive, low reagent and sample consumption and high throughput analysis of antioxidant activity. The paper-based device was fabricated using a lamination method to create a 5-mm in diameter circular test zone that was embedded with a DPPH reagent. The analysis was carried out in one-step by dropping an antioxidant/sample onto the test zone. After reduction by the antioxidant, the DPPH radicals become stable DPPH molecules, resulting in a change in color from deep violet to pale yellow. The violet color intensity of DPPH was inversely proportional to the antioxidant activity of the samples, and was measured using imaging software. A high precision and a low limit of detection were found in the analysis of six standard antioxidants including gallic acid, trolox, ascorbic acid, caffeic acid, vanilliic acid and quercetin. The device was then validated against the traditional spectrophotometric DPPH assay by analyzing the antioxidant activity of 7 tea samples. The results showed no significant difference for gallic acid equivalent for all 7 samples obtained from the two methods at the 95% confidence level, indicating that the developed method was reliable for antioxidant activity analysis of real samples. Finally, the paper-based DPPH device was found to be stable over 10 days when stored in a refrigerator (2 - 4°C), making it an easy-to-use device for end-users.

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Section: Introductionmentioning

confidence: 99%

Paper-based DPPH Assay for Antioxidant Activity Analysis

2018

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“…4 TMAH-doped starch films were used in conjunction with digital image colorimetry (DIC) instead of conventional spectrophotometric measurement 7,16,[26][27][28] for rapid quantitative analysis. DIC makes on-site TNT detection more convenient and cost effective because it employs cheaper portable detection devices, e.g., a digital camera [29][30][31][32][33][34] or smartphone, [4][5][6]8,31 instead of a spectrophotometer. In the work described in this article, a widely commercially available webcam was used to photograph the colorimetric product obtained from the film developed.…”

Section: Introductionmentioning

confidence: 99%

Tetramethylammonium Hydroxide-doped Starch Film as a Colorimetric Sensor for Trinitrotoluene Detection

et al. 2020

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A tetramethylammonium hydroxide (TMAH)-doped starch film was developed for trinitrotoluene (TNT) detection. A purple Janowsky anion was obtained from the reaction of TNT with released TMAH. When the film was used in conjunction with digital image colorimetry (DIC), rapid quantitative analysis of TNT was achieved. The Red-Green-Blue (RGB) intensities analyzed from digital photographs of the purple product were used to establish calibration curves for TNT. A wide linear range (2.5 to 50 mgL-1) with good linearity (R 2 > 0.99) was achieved for the quantification of TNT. Good precision (1.73 to 3.74%RSD) was obtained for inter-day tests (n = 5). The films were applied to test four postblast soil samples and two positive results were observed. The concentrations quantified by DIC were in good agreement with spectrophotometry. The film was able to be stored in a freezer for 3 months with <4.3% change in performance.

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“…Asano and Shiraishi developed a microfluidic paper device printed by a 3D printer to detect Cr(VI) ion. 8 The intensities of green components in images of the analyte-dropped paper devices captured by a digital camera were analyzed with ImageJ software. This allowed the detection of 30 ppm Cr(VI) ions.…”

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confidence: 99%