A novel, simple and low-cost paper-based analytical device for colorimetric detection of Cronobacter spp.

A detection method for type-II pyrethroids in an environmental water sample using a microfluidic paper-based analytical device (µPAD) is reported here. The detection approach is based on the formation of cyanide from the hydrolysis of type-II pyrethroids and the colorimetric detection of cyanide on a layer-based µPAD. Parafilm and inexpensive laminating pouches were used to create a hydrophobic barrier for the assay on the µPAD. This detection approach was selective to type-II pyrethroids in water for which an environmental water sample was tested. The calibration curves for cypermethrin, deltamethrin, cyhalothrin, and fenvalerate ranged from 2 to 40 µg/mL without sample preconcentration. The lower concentrations of type-II pyrethroids can be assessed by including a preconcentration step prior to the detection on a µPAD. This detection system provides an alternative platform for fast, semiquantitative testing for pesticide contamination in environmental surface water by allowing for portability, low reagent/sample consumption, and low-cost testing.

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Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

Open Chemistry ◽

10.1515/chem-2020-0031 ◽

2020 ◽

Vol 18 (1) ◽

pp. 303-313 ◽

Cited By ~ 1

Author(s):

Aamir Rasheed ◽

Tahseen Ghous ◽

Sumaira Mumtaz ◽

Muhammad Nadeem Zafar ◽

Kalsoom Akhter ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Low Cost ◽

Colorimetric Detection ◽

Time Flow ◽

Highly Sensitive ◽

Glass Column ◽

On Line ◽

Preconcentration Time ◽

Ultra Trace

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

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Molecularly imprinted electrospun fiber membrane for colorimetric detection of hexanoic acid

e-Polymers ◽

10.1515/epoly-2021-0049 ◽

2021 ◽

Vol 21 (1) ◽

pp. 500-510

Author(s):

Xiaoguang Ying ◽

Jieyuan He ◽

Xiao Li

Keyword(s):

Low Cost ◽

Electrospun Fiber ◽

Colorimetric Detection ◽

Hexanoic Acid ◽

Bromocresol Purple ◽

Fiber Membrane ◽

Color Changes ◽

Before And After ◽

The Difference ◽

Imagej Software

Abstract An imprinted electrospun fiber membrane was developed for the detection of volatile organic acids, which are key components of human body odor. In this study, hexanoic acid (HA) was selected as the target, polymethyl methacrylate (PMMA) was used as the substrate, and colorimetric detection of HA was achieved by a bromocresol purple (BCP) chromogenic agent. The results showed that the morphology of the fiber membrane was uniform and continuous, and it showed excellent selectivity and specificity to HA. Photographs of the color changes before and after fiber membrane adsorption were recorded by a camera and quantified by ImageJ software by the difference in gray value (ΔGray). This method is simple, intuitive, and low cost and has great potential for application in human odor analysis.

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A ratiometric colorimetric detection of the folate receptor based on terminal protection of small-molecule-linked DNA

The Analyst ◽

10.1039/c4an02115k ◽

2015 ◽

Vol 140 (4) ◽

pp. 1260-1264 ◽

Cited By ~ 15

Author(s):

Yanhong Zhu ◽

Guangfeng Wang ◽

Liang Sha ◽

Yuwei Qiu ◽

Hong Jiang ◽

...

Keyword(s):

Small Molecule ◽

Crucial Role ◽

Folate Receptor ◽

Low Cost ◽

Colorimetric Detection ◽

Cancer Therapeutics ◽

Selective Detection

Development of strategies for the sensitive and selective detection of the folate receptor (FR) that are simple and low cost is of great importance for assessing cancer therapeutics due to its crucial role in physiological, pharmacological and pathological processes.

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Molecular Diagnostic of Ochratoxin A with Specific Aptamers in Corn and Groundnut via Fabrication of A Microfluidic Device

10.21203/rs.3.rs-1041799/v1 ◽

2021 ◽

Author(s):

Deepshikha Shahdeo ◽

Azmat Ali Khan ◽

Amer M Alanazi ◽

Yun Suk Huh ◽

Shruti Shukla ◽

...

Keyword(s):

Ochratoxin A ◽

Limit Of Detection ◽

Colorimetric Assay ◽

Animal Health ◽

Colorimetric Detection ◽

Molecular Diagnostic ◽

Detection Range ◽

Vis Spectroscopy ◽

Wide Range ◽

Analytical Device

Abstract Ochratoxin A (OTA) is one of the predominant mycotoxins that contaminate a wide range of food commodities. In the present study, a 36-mer aptamer was used as a molecular recognition element coupled with gold nanoparticles (AuNPs) for colorimetric detection of OTA in a microfluidic paper-based analytical device (µPADs). The µPADs consisted of three zones: control, detection, and sample, interconnected by channels. The biophysical characterizations of aptamer conjugated AuNPs were done by UV-vis spectroscopy (UV-vis), dynamic Light Scattering (DLS), and transmission electron microscopy (TEM). The developed colorimetric assay for OTA showed a limit of detection of 242, 545, and 95.69 ng/mL in water, corn, and groundnut, respectively. The HPLC detection method achieved acceptable coefficient in standard curves (r2 = 0.9995), better detection range, and recovery rates in spiked corn and groundnut samples as 43.61 ± 2.18% to 87.10 ± 1.82% and 42.01 ± 1.31% to 86.03 ± 2.64% after multiple sample extractions and cleanup steps. However, the developed µPADs analytical device had the potent ability to rapidly detect OTA without any extraction pre-requirement, derivatization, and cleanup steps, thus illustrating its feasibility in the animal health sector, agricultural, and food industries.

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Dual-Modal Assay Kit for the Qualitative and Quantitative Determination of the Total Water Hardness Using a Permanent Marker Fabricated Microfluidic Paper-Based Analytical Device

Chemosensors ◽

10.3390/chemosensors8040097 ◽

2020 ◽

Vol 8 (4) ◽

pp. 97

Author(s):

Oyejide Damilola Oyewunmi ◽

Seyed Hamid Safiabadi-Tali ◽

Sana Jahanshahi-Anbuhi

Keyword(s):

Ethylenediaminetetraacetic Acid ◽

Limit Of Detection ◽

Low Cost ◽

Water Hardness ◽

Sample Introduction ◽

World Health ◽

Total Hardness ◽

Quantitative Detection ◽

Qualitative And Quantitative ◽

Analytical Device

A dip-and-read microfluidic paper-based analytical device (µPAD) was developed for the qualitative and quantitative detection of the total hardness of water. To create well-defined hydrophobic barriers on filter paper, a regular office printer and a commercially available permanent marker pen were utilized as a quick and simple technique with easily accessible equipment/materials to fabricate µPAD in new or resource-limited laboratories without sophisticated equipment. After a wettability and barrier efficiency analysis on the permanent marker colors, the blue and green ink markers exhibited favorable hydrophobic properties and were utilized in the fabrication of the developed test devices. The device had five reaction and detection zones modeled after the classification given by the World Health Organization (WHO), so qualitatively it determined whether the water was ‘soft’, ‘moderately hard’, ‘hard’, or ‘very hard’ by changing color from blue to pink in about 3 min. The device was also used to introduce an alternative colorimetric reaction for quantitative analysis of the water hardness without the need for ethylenediaminetetraacetic acid (EDTA) and without compromising the simplicity and low cost of the device. The developed µPAD showed a calculated limit of detection (LOD) of 0.02 mM, which is at least 80% less than those of commercially available test strips and other reported µPADs, and the results of the real-world samples were consistent with those of the standard titration (with EDTA). In addition, the device exhibited stability for 2 months at room and frigid condition (4 °C) and at varying harsh temperatures from 25 to 100 °C. The results demonstrate that the developed paper-based device can be used for rapid, on-site analysis of water with no interferences and no need for a pipette for sample introduction during testing.

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Ultrasensitive colorimetric detection of Hg2+ ions based on enhanced catalytic performance of gold amalgam dispersed in channels of rose petals

The Analyst ◽

10.1039/c8an02075b ◽

2019 ◽

Vol 144 (4) ◽

pp. 1205-1209 ◽

Cited By ~ 4

Author(s):

Chi Zhang ◽

Caiyun Kong ◽

Qingyun Liu ◽

Zhengbo Chen

Keyword(s):

Gold Nanoparticles ◽

Pore Structure ◽

Low Cost ◽

Colorimetric Detection ◽

Catalytic Performance ◽

Mercury Ions ◽

Colorimetric Sensing ◽

Rose Petals

We herein present a simple, low-cost, and ultrasensitive colorimetric sensing strategy for the detection of mercury ions (Hg2+) that takes advantage of the natural pore structure in rose petals to encapsulate gold nanoparticles (AuNPs).

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Engineering of Bifunctional Enzymes with Uricase and Peroxidase Activities for Simple and Rapid Quantification of Uric Acid in Biological Samples

Catalysts ◽

10.3390/catal10040428 ◽

2020 ◽

Vol 10 (4) ◽

pp. 428

Author(s):

Thanawat Phuadraksa ◽

Jurairat Chittrakanwong ◽

Kittitouch Tullayaprayouch ◽

Naruthai Onsirisakul ◽

Sineewanlaya Wichit ◽

...

Keyword(s):

Uric Acid ◽

Low Cost ◽

Colorimetric Detection ◽

Amplex Red ◽

Bifunctional Enzymes ◽

Bifunctional Proteins ◽

Frame Fusion ◽

The Cost ◽

Optimized Conditions ◽

Catalyzed Oxidation

Serum uric acid (SUA) is an important biomarker for prognosis and management of gout and other diseases. The development of a low-cost, simple, rapid and reliable assay for SUA detection is of great importance. In the present study, to save the cost of enzyme production and to shorten the reaction time for uric acid quantification, bifunctional proteins with uricase and peroxidase activities were engineered. In-frame fusion of Candida utilis uricase (CUOX) and Vitreoscilla hemoglobin (VHb) resulted in two versions of the bifunctional protein, CUOX-VHb (CV) and VHb-CUOX (VC). To our knowledge, this is the first report to describe the production of proteins with uricase and peroxidase activities. Based on the measurement of the initial rates of the coupled reaction (between uricase and peroxidase), CV was proven to be the most efficient enzyme followed by VC and native enzymes (CUOX+VHb), respectively. CV was further applied for the development of an assay for colorimetric detection of SUA, which was based on VHb-catalyzed oxidation of Amplex Red in the presence of hydrogen peroxide (H2O2). Under the optimized conditions, the assay exhibited a linear relationship between the absorbance and UA concentration over the range of 2.5 to 50 μM, with a detection limit of 1 μM. In addition, the assay can be performed at a single pH (8.0) so adjustment of the pH for peroxidase activity was not required. This advantage helped to further reduce costs and time. The developed assay was also successfully applied to detect UA in pooled human serum with the recoveries over 94.8%. These results suggest that the proposed assay holds great potential for clinical application.

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Colorimetric detection of quaternary ammonium surfactants using citrate-stabilized gold nanoparticles (Au NPs)

Analytical Methods ◽

10.1039/c3ay42287a ◽

2014 ◽

Vol 6 (7) ◽

pp. 2031-2033 ◽

Cited By ~ 16

Author(s):

Li-Qing Zheng ◽

Xiao-Dong Yu ◽

Jing-Juan Xu ◽

Hong-Yuan Chen

Keyword(s):

Gold Nanoparticles ◽

Quaternary Ammonium ◽

Low Cost ◽

Colorimetric Detection ◽

Hydrophobic Effect ◽

Colorimetric Method ◽

Au Nps ◽

Quaternary Ammonium Surfactants

Based on the hydrophobic effect inducing the aggregation of Au NPs, a rapid and low-cost colorimetric method for detection of quaternary ammonium surfactants using citrate-stabilized AuNPs was developed.

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