A novel colorimetric indicator for ethanol detection in preserved baby mangoes

Cellulose hydrogels are often prepared from native cellulose through a direct cellulose dissolution approach that often involves tedious process and solvent recovery problems. A self-supporting cellulose hydrogel was prepared by gelation of the TEMPO-oxidized bagasse cellulose nanofibrils (CNF) triggered by strong crosslinking between carboxylate groups and Zn2+. TEMPO process was used to generate negatively charged carboxylate groups on CNF surface to provide a high binding capability to Zn2+. Three TEMPO-oxidized CNFs of different carboxylate contents were prepared and characterized. TEM and AFM microscopes suggested that the sizes of CNFs were fined down and carboxylated cellulose nanofibrils (TOCNFs) of 5–10 nm wide, 200–500 nm long, and carboxylate contents 0.73–1.29 mmol/g were obtained. The final structures and compressive strength of hydrogels were primarily influenced by interfibril Zn2+-carboxylate interactions, following the order of TOCNFs concentration > content of carboxylate groups > concentration of zinc ions. A CO2 sensitive self-supporting cellulose hydrogel was developed as a colorimetric indicator of food spoilage for intelligent food packaging applications.

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Monitoring of oxygen using colorimetric indicator based on graphene/TiO2composite with first-order kinetics of methylene blue for modified atmosphere packaging

Packaging Technology and Science ◽

10.1002/pts.2384 ◽

2018 ◽

Vol 31 (9) ◽

pp. 575-584

Author(s):

Shuting Huang ◽

Huijie Li ◽

Yixiang Wang ◽

Xinghai Liu ◽

Houbin Li ◽

...

Keyword(s):

Methylene Blue ◽

Modified Atmosphere Packaging ◽

Modified Atmosphere ◽

First Order ◽

First Order Kinetics ◽

Colorimetric Indicator ◽

Kinetics Of

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Antifungal Susceptibility Testing of Malassezia spp. with an Optimized Colorimetric Broth Microdilution Method

Journal of Clinical Microbiology ◽

10.1128/jcm.00338-17 ◽

2017 ◽

Vol 55 (6) ◽

pp. 1883-1893 ◽

Cited By ~ 22

Author(s):

Cheryl Leong ◽

Antonino Buttafuoco ◽

Martin Glatz ◽

Philipp P. Bosshard

Keyword(s):

Susceptibility Testing ◽

Skin Diseases ◽

Antifungal Susceptibility ◽

Drug Susceptibility ◽

Drug Susceptibility Testing ◽

Broth Microdilution ◽

Content Type ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Colorimetric Indicator

ABSTRACTMalasseziais a genus of lipid-dependent yeasts. It is associated with common skin diseases such as pityriasis versicolor and atopic dermatitis and can cause systemic infections in immunocompromised individuals. Owing to the slow growth and lipid requirements of these fastidious yeasts, convenient and reliable antifungal drug susceptibility testing assays forMalasseziaspp. are not widely available. Therefore, we optimized a broth microdilution assay for the testing ofMalasseziathat is based on the CLSI and EUCAST assays forCandidaand other yeasts. The addition of ingredients such as lipids and esculin provided a broth medium formulation that enabled the growth of allMalasseziaspp. and could be read, with the colorimetric indicator resazurin, by visual and fluorescence readings. We tested the susceptibility of 52 strains of 13Malasseziaspecies to 11 commonly used antifungals. MIC values determined by visual readings were in good agreement with MIC values determined by fluorescence readings. The lowest MICs were found for the azoles itraconazole, posaconazole, and voriconazole, with MIC90values of 0.03 to 1.0 μg/ml, 0.06 to 0.5 μg/ml, and 0.03 to 2.0 μg/ml, respectively. AllMalasseziaspp. were resistant to echinocandins and griseofulvin. SomeMalasseziaspp. also showed high MIC values for ketoconazole, which is the most widely recommended topical antifungal to treatMalasseziaskin infections. In summary, our assay enables the fast and reliable susceptibility testing ofMalasseziaspp. with a large panel of different antifungals.

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Dissolved Carbon Dioxide Sensing Platform for Freshwater and Saline Water Applications: Characterization and Validation in Aquaculture Environments

Sensors ◽

10.3390/s19245513 ◽

2019 ◽

Vol 19 (24) ◽

pp. 5513

Author(s):

J.P. Mendes ◽

L. Coelho ◽

B. Kovacs ◽

J.M.M.M. de Almeida ◽

C.M. Pereira ◽

...

Keyword(s):

Carbon Dioxide ◽

Limit Of Detection ◽

Saline Water ◽

Light Emitting Diode ◽

Limit Of Quantification ◽

Acid Media ◽

Dissolved Carbon ◽

Sensing Platform ◽

Dissolved Carbon Dioxide ◽

Colorimetric Indicator

A sensing configuration for the real-time monitoring, detection, and quantification of dissolved carbon dioxide (dCO2) was developed for aquaculture and other applications in freshwater and saline water. A chemical sensing membrane, based on a colorimetric indicator, is combined with multimode optical fiber and a dual wavelength light-emitting diode (LED) to measure the dCO2-induced absorbance changes in a self-referenced ratiometric scheme. The detection and processing were achieved with an embeded solution having a mini spectrometer and microcontroller. For optrode calibration, chemical standard solutions using sodium carbonate in acid media were used. Preliminary results in a laboratory environment showed sensitivity for small added amounts of CO2 (0.25 mg·L−1). Accuracy and response time were not affected by the type of solution, while precision was affected by salinity. Calibration in freshwater showed a limit of detection (LOD) and a limit of quantification (LOQ) of 1.23 and 1.87 mg·L−1, respectively. Results in saline water (2.5%) showed a LOD and LOQ of 1.05 and 1.16 mg·L−1, respectively. Generally, performance was improved when moving from fresh to saline water. Studies on the dynamics of dissolved CO2 in a recirculating shallow raceway system (SRS+RAS) prototype showed higher precision than the tested commercial sensor. The new sensor is a compact and robust device, and unlike other sensors used in aquaculture, stirring is not required for correct and fast detection. Tests performed showed that this new sensor has a fast accurate detection as well as a strong potential for assessing dCO2 dynamics in aquaculture applications.

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Preparation and Characterization of Colorimetric Indicator Films Based on Chitosan/Polyvinyl Alcohol and Anthocyanins from Agri-Food Wastes

Journal of Polymers and the Environment ◽

10.1007/s10924-020-01978-3 ◽

2020 ◽

Author(s):

Cristiane Capello ◽

Thalles Canton Trevisol ◽

Jaine Pelicioli ◽

Manoela Bernardes Terrazas ◽

Alcilene Rodrigues Monteiro ◽

...

Keyword(s):

Polyvinyl Alcohol ◽

Food Wastes ◽

Colorimetric Indicator

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Colorimetric Detection of Trace Arsenic(III) in Aqueous Solution Using Arsenic Aptamer and Gold Nanoparticles

Australian Journal of Chemistry ◽

10.1071/ch13512 ◽

2014 ◽

Vol 67 (5) ◽

pp. 813 ◽

Cited By ~ 49

Author(s):

Minglei Yu

Keyword(s):

Aqueous Solution ◽

Gold Nanoparticles ◽

Detection Limit ◽

Colorimetric Assay ◽

Colorimetric Detection ◽

Colour Change ◽

Colorimetric Sensing ◽

Detection Range ◽

Colorimetric Indicator ◽

Blue Solution

In this study, trace arsenic(iii) (AsIII) in aqueous solution was detected by applying a classical aptamer-based gold nanoparticles colorimetric sensing strategy. An arsenic aptamer was used as a sensing probe and gold nanoparticles as a colorimetric indicator. In the absence of AsIII, the gold nanoparticles were stabilised by the arsenic aptamer and remained dispersed at high NaCl concentrations, displaying a red solution. Contrarily, in the presence of AsIII, the gold nanoparticles were prone to aggregation, owing to the formation of aptamer–AsIII complex between the arsenic aptamer and AsIII, and thus exhibited a blue solution. By monitoring the colour change, a simple and fast colorimetric assay for AsIII was established with a detection range of 1.26–200 ppb and a detection limit of 1.26 ppb. Because this colorimetric assay only involves common reagents and can be assessed visually, it holds great potential for arsenic(iii) monitoring in environment-related and other applications.

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