Simple colorimetric ammonium assay employing well microplate with gas pervaporation and diffusion for natural indicator immobilized paper sensor via smartphone detection

Greening sample preparation: An overview of cutting-edge contributions

“…Nanomaterials have been used for optical sensing [24,25], although natural indicators (e.g. butterfly pea flower extract) [27] have also found applicability in these systems.…”

Cost-effective and sensitive anthocyanin-based paper sensors for rapid ammonia detection in aqueous solutions

“…However, these methods suffer from issues such as the use of toxic or unstable reactants (e.g., mercury, phenol, hypochlorite, sodium nitroprusside), sample pretreatment, catalyst requirement, long reaction time, and toxic byproducts (e.g., o-chloro-phenol). 5,12,16,17 Sequential injection gas diffusion device, 18 microuidic paper-based analytical device (mPAD), 19 uorescence detection, 20 and paperbased sensors fabricated with solid Berthelot reagents, 21 are examples of other ammonia detection methods. Sensitivity to the temperature and pH change, wetting and clogging of the membrane, low sensor sensitivity, the use of toxic chemicals, and complicated sensor fabrication process are some limitations associated with these methods.…”

“…Sensitivity to the temperature and pH change, wetting and clogging of the membrane, low sensor sensitivity, the use of toxic chemicals, and complicated sensor fabrication process are some limitations associated with these methods. 5,17 Therefore, there is still a requirement to develop a rapid, sensitive, environmentally friendly, straightforward, and cost-effective ammonia detection method.…”

“…[22][23][24][25] Cost-effectiveness, convenience, and versatility are some advantages of these paper-based sensing methods. 17,26 Anthocyanins extracted from plants, vegetables, or fruits are natural pH indicators that can be used as active material in paper sensors as a substitute for synthetic indicators. Although this material is non-toxic and water-soluble, there are only few reports in which anthocyanin-based papers, bers, and polymer lms were used to detect ammonia in aqueous or gaseous forms.…”

“…Although this material is non-toxic and water-soluble, there are only few reports in which anthocyanin-based papers, bers, and polymer lms were used to detect ammonia in aqueous or gaseous forms. 17,[27][28][29][30] Early studies only focused on anthocyanin extraction from one anthocyanin source and sensor fabrication to detect ammonia in aqueous or gaseous samples. However, the effect of different anthocyanin sources on the sensor performance is not investigated.…”