Monitoring Acid–Base Titrations on Wax Printed Paper Microzones Using a Smartphone

Nogueira, Sandro A.; Sousa, Lucas R.; Silva, Nathália K. L.; Rodrigues, Pedro H. F.; Coltro, Wendell K. T.

doi:10.3390/mi8050139

Cited by 41 publications

(26 citation statements)

References 31 publications

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“…A summary of immunoassay based lPADs is given in Table II. There are also lPADs designed for the analysis of certain chemicals [98][99][100] (e.g., explosives, synthetic compounds, pharmaceuticals, and organic molecules), the detection of microorganisms in environmental resources, 101 blood typing, 66 hepatoxicity, 65 acid-base titration, 102 infection detection, 103 and nucleic acid detection. 69,104 lPADs can also be used for the multiple detection of metals such as nickel, copper, iron, cadmium, chromium, or lead.…”

Section: B Lpads Designed For Detection and Analysismentioning

confidence: 99%

A review on wax printed microfluidic paper-based devices for international health

2017

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Paper-based microfluidics has attracted attention for the last ten years due to its advantages such as low sample volume requirement, ease of use, portability, high sensitivity, and no necessity to well-equipped laboratory equipment and well-trained manpower. These characteristics have made paper platforms a promising alternative for a variety of applications such as clinical diagnosis and quantitative analysis of chemical and biological substances. Among the wide range of fabrication methods for microfluidic paper-based analytical devices (PADs), the wax printing method is suitable for high throughput production and requires only a commercial printer and a heating source to fabricate complex two or three-dimensional structures for multipurpose systems. PADs can be used by anyone for diagnosis and analysis; therefore, wax printed PADs are promising especially in resource limited environments where people cannot get sensitive and fast diagnosis of their serious health problems and where food, water, and related products are not able to be screened for toxic elements. This review paper is focused on the applications of paper-based microfluidic devices fabricated by the wax printing technique and used for international health. Besides presenting the current limitations and advantages, the future directions of this technology including the commercial aspects are discussed. As a conclusion, the wax printing technology continues to overcome the current limitations and to be one of the promising fabrication techniques. In the near future, with the increase of the current interest of the industrial companies on the paper-based technology, the wax-printed paper-based platforms are expected to take place especially in the healthcare industry.

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Section: B Lpads Designed For Detection and Analysismentioning

confidence: 99%

A review on wax printed microfluidic paper-based devices for international health

2017

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“…These issues pose difficulties with real sample analysis with paper-based acid–base titration. Later, Nogueira et al 19 fabricated paper microzones to monitor acid–base titration through a free APP named Photometrix. The redox titrations have also been reported using μPADs.…”

Section: Introductionmentioning

confidence: 99%

Indicator-Free Argentometric Titration for Distance-Based Detection of Chloride Using Microfluidic Paper-Based Analytical Devices

et al. 2020

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We described an indicator-free argentometric titration strategy using a microfluidic paper-based analytical device. This strategy was based on the formation of insoluble silver salts by reactions occurring between analytes and titrant (Ag + ) on a paper channel. After the insoluble silver salts were formed and precipitated on the channel, the paper substrate modified with the surplus titrant on the channel turned reddish-brown by exposure of the devices to a simple and cheap UV light source for 5 min, generating a colored band on the channel. Distance-based detection of chloride was achieved by measuring the length of the colored band with a detection limit of 1.7 mg L –1 Cl – . This method was used to detect chlorides in tap water, with an analytical result (10.1 ± 1.2 mg L –1 ) agreeing well with that obtained by a classical conventional precipitation titration (9.8 mg L –1 ), which was based on the measurement of the consumed volume of titrant. This paper-based precipitation titration method is free of skilled personnel and has advantages of low reagent/sample consumption, disposability, portability, and simple operation over the conventional precipitation titration. More importantly, being free of any indicator, this method may be used to detect more species than the conventional precipitation titrations, which are limited by the indicator, for example, CO 3 2– and SO 4 2– , which could form insoluble silver salts in aqueous liquids. Additionally, comparing with most of those paper-based titrimetry reported previously, this presented precipitation titration is free of any indicator or ion selective electrode to detect the end point of titration.

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“…In this context, we used a free software app called PhotoMetrix [15] to estimate the enzymatic activity of endoglucanase enzymes. PhotoMetrix has been used for efficiently helping to determine iron in vitamin supplement tablets [16], iodine in biodiesel [17], ethanol in sugarcane spirit samples [18], and for monitoring of acid-base titrations on paper platforms [19], estimation of pH in milk samples [20] and chromium speciation in leather samples [21].…”

Section: Introductionmentioning

confidence: 99%

Easy Estimation of Endoglucanase Activity Using a Free Software App for Mobile Devices

Pereira¹,

Guedes²,

Lucena³

et al. 2020

Br J Anal Chem

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Imaging-PLS was applied for cellulase enzymes from Aspergillus niger and Trichoderma reesei This study describes the estimation of the enzymatic activity of endoglucanase based on the 3,5-dinitrosalicylic acid (DNS) method and carboxymethylcellulose (CMC) substrate using glucose as the analyte. As an alternative to measuring the colored product obtained by the reaction between glucose and DNS, a free software app for mobile devices was used for estimating the color intensity of solutions, replacing the need of a UV-Vis spectrophotometer (reference method). The app is able to convert images in color histograms to red (R), green (G) and blue (B) scales and to provide univariate and multivariate calculations of the image data. The chemometric technique partial least squares (PLS) was employed with the app and presented accurate results that were comparable to those of the reference method. A correlation coefficient of 0.983 was obtained for the linear range between 0.60 and 2.60 mg mL-1 of glucose, and the standard error of cross-validation (SECV) was 0.219 mg mL-1. The proposed method (imaging-PLS) was applied for samples of cellulase enzymes from Aspergillus niger and Trichoderma reesei, revealing an interesting alternative to estimate the enzymatic activity of endoglucanase.

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Monitoring Acid–Base Titrations on Wax Printed Paper Microzones Using a Smartphone

Cited by 41 publications

References 31 publications

A review on wax printed microfluidic paper-based devices for international health

A review on wax printed microfluidic paper-based devices for international health

Indicator-Free Argentometric Titration for Distance-Based Detection of Chloride Using Microfluidic Paper-Based Analytical Devices

Easy Estimation of Endoglucanase Activity Using a Free Software App for Mobile Devices

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