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Overcoming lithium analysis difficulties with a simple colorimetric/spectrophotometric method 

Lucas F. Quartarolli, Alceu T. Silveira and Henrique E. Toma * 

The analytical determination of lithium ions is usually performed by atomic absorption and X-ray fluorescence methods. Chemical analysis based on polyfluoroporphyrin chromogenic methods is also being employed, especially for biological samples. However, all existing methods are expensive and not suitable for routine work or field assays. The alternative method proposed here is based on the formation of a LiKFe(IO6) compound which is converted into a tris(1,10-phenanthroline)iron(II) complex and monitored by spectrophotometric or colorimetric methods, the latter using a smartphone app. Under similar conditions, these two methods proved superior to the X-ray fluorescence method. A one pot analysis of lithium ions is also described, using an Eppendorf microtube previously modified for performing reaction, filtration and detection. This method is simple and very convenient for didactic and field assays.

DOI: 10.1039/d1ay00937k
This journal is © The Royal Society of Chemistry 2021

Color Analysis of Batik Fabric by Facile Smartphone Colorimetry 

Yaowarat Sirisathitkula, Suvita Kaewareelapb

The color of a textile material is the first attribute and key component considered by consumers while purchasing cloth.
However, measurement of fabric color is a very challenging task in the textile fabrication process. Colorimeters aids this measurement by adding objective assessments to a generally subjective process. The colorimeter application in Android smartphones provides a simple alternative to dedicated colorimetric devices. The purpose of this study was to determine the suitability of the smartphone colorimetry application for a Batik fabric color measurement. The colors of various Batik fabric images in the International Commission on Illumination L*a*b* color space, which includes all the colors that are visible by the human eye, obtained by a spectrophotometer and the colorimeter application were compared. Data of Batik fabric images acquired at three different distances of 10, 20, and 30 cm were analyzed. The color differences between the colorimeter and spectrophotometer results are various depending on the distance from the target. The ΔE* ab and ΔE* ch metrics were used to evaluate the color differences between the reference and sample fabric colors. The lowest mean of ΔE* ab values was 12.11  5.29 measured 20 cm away from each fabric. The mean values of ΔE* ab between pairs of color symbols from the Colorimeter application were comparable to those obtained by the spectrophotometer. The ΔE* ab values were more suitable for fabric color measurement than ΔE* ch. The results indicate that smartphone colorimetry provides reasonable accuracy, is simple to use for amateurs, suitable for fabric color matching, and can satisfy fabric market requirements. 

IJASEIT is licensed under a Creative Commons Attribution-Share Alike 4.0 International License

Application of Digital Colorimeter for Preliminary Characterization of Gold Nanoparticle Swarms Produced by Termitomyces heimii Using a novel Bioinspired Microfluidics Assay

Sujata Dabolkar,  Nandkumar M. Kamat

In our laboratory work extending over several years we have successfully studied the biogeochemical role of termite mounds and their occupants the termites and the exosymbiont fungus-Termitomyces. Fungi appear to be promising for large scale production of nanoparticles (NPs) as these are simpler to grow both in laboratory and at industrial scale. This paper reports a novel microfluidic based assay system to detect Gold bioreduction capacity of different tissues in tissue based and cell free environment. Using sterile microtest wells, different tissues such as umbo, pileus, lamellae, stipe context, stipe epicutis, pseudorrhiza context, pseudorrhiza epicutis of Termitomyces heimii mature fruitbodies were tested with 200μl chloroauric acid (one mM) and after an interval of 5, 10, 15, 30, 45, 60, 120 min and 12, 24 and 48 hours. The results in terms production of distinct nanoparticles were directly visualized microscopically and using mobile based digital colorimeter. Membrane filtered sterile water soluble extracts (SWSE) from the same tissues were similarly screened. The results manifested by mono and polydisperse GNPs and microparticles of mixed size groups demonstrated that cell free system can be potentially useful for bioinspired fabrication of GNPs. Further work in this direction is in progress using several termitomyces pure cultures.

The copyright holder for this is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. All rights reserved.

Smart app-based on-field colorimetric quantification of mercury via analyte-induced enhancement of the photocatalytic activity of TiO2–Au nanospheres

Rini Ravindranath, Arun Prakash Periasamy, Prathik Roy, Yu-Wen Chen & Huan-Tsung Chang 

We have devised a unique strategy for highly sensitive, selective, and colorimetric detection of mercury based on analyte-induced enhancement of the photocatalytic activity of TiO2–Au nanospheres (TiO2–Au NSs) toward degradation of methylene blue (MB). Through electrostatic interactions, Au nanoparticles are attached to poly-(sodium 4-styreneulfonate)/poly(diallyldimethylammonium chloride) modified TiO2 nanoparticles, which then form an Au shell on each TiO2 core through reduction of Au3+ with ascorbic acid. Notably, the deposition of Hg species (Hg2+/CH3Hg+) onto TiO2–Au NSs through strong Au–Hg aurophilic interactions speeds up catalytic degradation of MB. The first-order degradation rates of MB by TiO2–Au NSs and TiO2–Au–Hg NSs are 1.4 × 10−2 min−1 and 2.1 × 10−2 min−1, respectively. Using a commercial absorption spectrometer, the TiO2–Au NSs/MB approach provides linearity (R2 = 0.98) for Hg2+ over a concentration range of 10.0 to 100.0 nM, with a limit of detection (LOD) of 1.5 nM. On the other hand, using a low-cost smartphone app that records the color changes (ΔRGB) of MB solution based on the red–blue–green (RGB) component values, the TiO2–Au NSs/MB approach provides an LOD of 2.0 nM for Hg2+ and 5.0 nM for CH3Hg+, respectively. Furthermore, the smartphone app sensing system has been validated for the analyses of various samples, including tap water, lake water, soil, and Dorm II, showing its great potential for on-line analysis of environmental and biological samples.

© 2021 Springer Nature Switzerland AG. Part of Springer Nature.

CdSe/CdS/ZnS nanocrystals decorated with Fe3O4 nanoparticles for point-of-care optomagnetic detection of cancer biomarker in serum

Anjum Qureshi, Ali Tufani, Gulcan Corapcioglu, Javed H.Niazi

Early diagnosis of a progressive cancer disease is currently limited due to lack of adequate point-of-care (PoC) diagnostic tools. PoC diagnosis enables detecting early signs of a disease and pave way to disease prevention. Here, we developed an immuno-optomagnetic quantum dots based PoC assay for early detection of a cancer biomarker, human epidermal growth factor receptor-2 (hErbB2) protein in serum. This assay utilizes immuno-optomagnetic quantum dots (MQDs-Ab2) nanoarchitectures with unique orientation comprised of core CdSe/CdS/ZnS QD nanocrystals surrounded by layers of magnetic Fe3O4 nanoparticles (MNPs) and a bioactivated borofloat PoC-chip (Ab1). The MQDs-Ab2 and the PoC-chips were designed to bind same hErbB2 analyte, but both bind with distinct epitopes. First, free hErbB2 protein from serum was captured by MQDs-Ab2 forming immuno-optomagnetic MQDs-Ab2-hErbB2 complex, which was isolated and presented to bioactivated PoC-chips. The immuno-optomagnetic signal from chips was directly visualized by naked-eye after exposing chips with a UV-torch and the signal was directly measured within 30 min by computing RGB intensities using a smartphone camera and a colorimeter-app. The immuno-optomagnetic QDs based PoC-chip exhibited the detection range of 620 pg mL−1 ∼5 ng mL−1 hErbB2 protein in serum. The MQDs-Ab2 rendered biospecificty, magnetic and optical functionality to PoC detection and provided advantages of speed, sensitivity, portability and low-cost, which is most desired in resource limited settings. The developed PoC chip assay provided an accurate quantitative cancer biomarker detection with high sensitivity and specificity that required no laboratory equipment and is also potentially applicable to the detection of many other biomarkers.

© 2020 Elsevier B.V. All rights reserved.

Evaluation of Tarsus Pigmentation in Chickens Fed with Different Levels of Xanthophyll Pigment: A Practical Application of the CIELab System

Rony Riveros Lizana, Otto Zea Mendoza and Carlos Vilchez Perales

Objective: The objective of this study was to evaluate a method to assess dermis pigmentation in broiler chickens in response to xanthophyll pigment inclusion in their feed. Materials and Methods: Ninety-six Cobb 500 birds were distributed in a completely randomized design and fed with different diet treatments, including 0.30, 0.50 and 0.90 g kgG1  of xanthophyll pigment extract from marigold, or a control diet without pigment inclusion. On 42th day, the pigmentation of the dermis was evaluated. For this study, the DSM® colorimetric score and CIELab system were used for comparative evaluations, the luminosity (L), redness (a*) and yellowness (b*) of the tarsus skin were recorded. The data obtained using both methods were subjected to Pearsonʼs correlation analysis. The CIELab data were subjected to ANOVA, Tukey test was used to compare the treatments mean. The non-parametric data were compared using the Kruskal‒Wallis test. The software R was used for statistical analysis. Results: The results showed a higher correlation (p<0.01) with the yellow spectrum (b* = 0.72) and a greater sensitivity with a significant effect (p<0.01) in response to pigment inclusion. Conclusion: A practical application of the CIELab spectrum has the capacity to evaluate skin pigmentation “in vivo” in broiler chicks with different levels of pigmentation.

DOI: 10.3923/ijps.2020.265.269

Copyright: © 2020 Rony Riveros Lizana et al

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