A smartphone-based colorimetry after dispersive liquid–liquid microextraction for rapid quantification of calcium in water and food samples

Peng, Bo; Zhou, Juanjuan; Xu, Jiamei; Fan, Mimi; Ma, Yongjun; Zhou, Min; Li, Tingting; Zhao, Shengguo

doi:10.1016/j.microc.2019.104072

Cited by 42 publications

(13 citation statements)

References 39 publications

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“…This leads to a fast semi-quantitative result. Individual differences in color recognition can be avoided using smartphone apps measuring the R, G and B value of the colored test solutions (Peng et al 2019) or of commercially available field test kits for selected soil contaminants like As (Haque et al 2016). Furthermore, there is no problem with the disposal of the chemicals, since everything is kept in the closed tubes.…”

Section: Field Applicationmentioning

confidence: 99%

Field-Tests versus Laboratory Methods for Determining Metal Pollutants in Soil Extracts

Zeiner

Pirkl

Cindrić

2019

Soil and Sediment Contamination: An International Journal

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Soil is one of the vehicles by which metals enter plants and groundwater. Compared to organic pollutants, metals do not biodegrade and are usually not mobile. In order to estimate the potential impact on groundwater, the amount of extractable metals from soil are thus of concern. Soil matrices represent quite a complex matrix; thus, the appropriate choice of sample preparation and analytical method is of great importance and challenging to ensure reliable and fast data while keeping labor and time need as low as possible. Soil extracts using acetic acid were analyzed, on the one hand, using classical analytical methods such as titrimetry (complexometry) and spectrophotometry, and on the other hand, by instrumental methods, including inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GF-AAS). The classical methods are characterized by higher limits of detection (LODs), nevertheless their application as screening method on-site is promising. Applying specific reagents, precise measurements can be obtained by photometry with LODs about 0.1 mg/L. Titrimetric methods can be used for specific single element determination and for determining the sum of certain metals at contaminated sites due to LODs around 60 mg/L.

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Section: Field Applicationmentioning

confidence: 99%

Field-Tests versus Laboratory Methods for Determining Metal Pollutants in Soil Extracts

Zeiner

Pirkl

Cindrić

2019

Soil and Sediment Contamination: An International Journal

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“…The colored image mainly consists of three color channels, i. e., RGB (Red, Blue and green), depending on the color change and intensity. [39,42] The calibration plot for any colorimetric change can be obtained using these unit pixel values.…”

Section: Introductionmentioning

confidence: 99%

“…This indicator can be prepared and the analysis can be conducted at home without the need of any laboratory setup or personal expertise. The Android app Color Grab [39,43,44] from Loomat, which is free of cost, was used to pick RGB data from the photographed images. The H-paper indicator we prepared was successfully tested on real milk samples (Fresh milk, packaged milk, and samples prepared from powdered milk), stored in a domestic fridge and on milk kept at room temperature for different durations.…”

Section: Introductionmentioning

confidence: 99%

A Smartphone Coupled Freshness Indicator Prepared by Rub‐coating of Hibiscus Flowers on Paper substrates for Visual Monitoring of the Spoilage of Milk

Chaithra

2022

ChemistrySelect

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This study developed an inexpensive and easy-to-use milk freshness indicator (H-Paper) by rub-coating hibiscus flowers onto paper. As per the best of our knowledge, this is the first example of a food quality indicator prepared by direct handrubbing of a natural halochromic material onto paper substrates. Unlike the previously reported colorimetric indicators from natural sources, our indicator does not require the extraction of anthocyanins from the natural product. The H-Paper undergoes a quantifiable color change from green to purple to pink corresponding to fresh, spoiling, and spoiled milk samples. Digital photographs of H-Paper treated with milk samples were acquired using a smartphone, and RGB indices were analyzed using a free application. The red chromatic shift was used as a parameter to quantify color change of H-Paper to follow the spoilage of milk. Anthocyanins present in the hibiscus flowers are responsible for this colorimetric response. This work demonstrates a proof-of-concept for directly rubcoating halochromic materials onto a substrate to fabricate food freshness indicators. The H-Paper indicator has advantages of naked-eye analysis, consumer-friendliness, and instrument-free operation. This requires neither any laboratory accessories nor the expertise of a trained analyst for its preparation and operation, which is appropriate for use in resource-limited settings.

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“…By evaluating the works that used smartphones for image acquisition and performed the external processing of the acquired data (Figure 1), we can see that these devices are explored in several areas, such as the detection of diseases and markers of diseases causing in the medical field, immunoassay, 18–27 quality control of the environment, 28–39 forensic analysis, 40–42 control and quality of beverages and food, 15,43–64 quality evaluation of pharmaceutical products, 54,65,66 fuel quality control, 67,68 pigments, 69 chemical education, kinetic studies, and chemical receptors 70–77 …”

Section: Introductionmentioning

confidence: 99%

PhotoMetrix and colorimetric image analysis using smartphones

Böck

Helfer

Costa

et al. 2020

Journal of Chemometrics

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The steady advances in technology employed in smartphones, coupled with the high availability and the ease access to these devices, increased the interest in applying it to analytical purposes. The main goal is to develop simple, fast, and low-cost analytical methods, generating immediate results. Different analytical strategies using smartphones have been proposed to identify or determine different analytes in a wide range of matrices. Some of them use the smartphone to capture the images, to process them, and to provide the analytical results. Others use this device just for image acquisition. In this context, this review aimed to relate previous works that used smartphones to acquire images for analytical purposes, with a special focus on PhotoMetrix application, which is a tool for chemical analysis. This application allows the decomposition of digital images acquired by smartphone cameras and to process them within the same device, allowing in situ chemical analysis.

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A smartphone-based colorimetry after dispersive liquid–liquid microextraction for rapid quantification of calcium in water and food samples

Cited by 42 publications

References 39 publications

Field-Tests versus Laboratory Methods for Determining Metal Pollutants in Soil Extracts

Field-Tests versus Laboratory Methods for Determining Metal Pollutants in Soil Extracts

A Smartphone Coupled Freshness Indicator Prepared by Rub‐coating of Hibiscus Flowers on Paper substrates for Visual Monitoring of the Spoilage of Milk

PhotoMetrix and colorimetric image analysis using smartphones

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