Scaling the Analytical Information Given by Several Types of Colorimetric and Spectroscopic Instruments Including Smartphones: Rules for Their Use and Establishing Figures of Merit of Solid Chemosensors

Abstract

The analytical information given by different types of instruments was scaled in order to establish suitably the figures of merit of a given methodology based on color measurements. Different lab and portable instruments, including smartphones with and without a miniaturized spectrophotometer accessory, have been tested. In order to obtain broad information and using objective criteria, these instruments have been compared from (1) the analytical point of view, considering mainly the detection limit (limits of detection [LODs]), selectivity, accuracy and intra- and interday precision, size, components, and costs; and (2) the environmental point of view, based on their footprint as kilograms of CO 2 . No significant differences in the precision were obtained with RSD (%) values lower than 10% for all of the instruments, but the achieved values of LOD, selectivity, accuracy, and cost were different. Footprints of CO 2 were better for portable instrumentation, especially for smartphones. Three solid chemosensors made of different materials (PDMS, paper, or nylon) have been tested for the determination of ammonia and hydrogen sulfide at different concentration levels (ppb levels). As a result of this study, some rules for selecting the instrument for obtaining the required information have been established. Two apps have been developed for quantitation by smartphones, one for working with RGB values and the other for spectra obtained by the miniaturized spectrophotometer coupled to a smartphone.

Improving Sustainability of the Griess Reaction by Reagent Stabilization on PDMS Membranes and ZnNPs as Reductor of Nitrates: Application to Different Water Samples

“…The size of the membrane used was reduced according to the volume used. In this case, the absorbance could be measured by a microplate reader or by RGB coordinates obtained from the digital images captured by using a smartphone [ 17 , 31 ].…”

“…To determinate nitrates, prior to the Griess reaction, the appropriate volume of dispersed ZnNPs or nylon membrane with ZnNPs as a reducing agent was added. The smartphone images were captured and processed [ 31 ].…”

Functional Micro-/Nanostructures in Agrofood Science: Precise Inspection, Hazard Elimination, and Potential Health Risks

“…The properties can enable a simpler, faster, more efficient, and more sensitive detection process, which can compensate for the shortcomings of traditional techniques. , In recent years, micro-/nanomaterial-based detection technologies have mainly been used in combination with biosensors to enhance detectability and efficiency . It should be noted that in recent years, researchers have introduced smartphones in nanomaterial-based detection technologies. − The portability of smartphones enables on-site analysis of food hazards, that has greatly simplified the analysis steps and shortened the detection time. , Meanwhile, the powerful data processing and analysis ability of smartphones also confer higher accuracy of detection results. , It can be used as a complement to traditional detection techniques for rapid risk screening and on-site testing . In addition, based on the strong adsorption capacity and magnetic separation performance of some micro-/nanomaterials, micro-/nanomaterials are also often used to eliminate food hazards. − …”

Advances in the Measurement of Polymeric Colorimetric Sensors Using Portable Instrumentation: Testing the Light Influence

“…In situ analysis is a trending topic in the field of analytical chemistry. One option proposed to address this challenge is to use sensors combined with portable instrumentation [ 1 ]. In this context, Campíns-Falcó et al proposed the use of polymers as supporting materials to embed chromogenic [ 1 ] or fluorescent [ 2 ] reagents.…”

“…One option proposed to address this challenge is to use sensors combined with portable instrumentation [ 1 ]. In this context, Campíns-Falcó et al proposed the use of polymers as supporting materials to embed chromogenic [ 1 ] or fluorescent [ 2 ] reagents. Between these materials, polydimethyl siloxane (PDMS) stands out.…”