pH and CO2 Sensing by Curcumin-Coloured Cellophane Test Strip

Abstract

2 pH and CO 2 sensing by curcumin coloured cellophane test strip ABSTRACTCurcumin coloured cellophane test strip -fabricated without any synthetic material -is used to determine in situ the instantaneous pH changes in liquids and in the air. A low cost, portable sensor array for possible medical and food-industrial application is developed. Next to the pH detection, curcumin coloured test strip can be applied as CO 2 monitoring sensor, too. On-going processes and the structural changes are followed by UV-VIS spectrophotometer, ATR-FTIR and AFM.

Smartphone-Based Extension of the Curcumin/Cellophane pH Sensing Method

“…Based on previous results curcumin-coloured (Pávai et al 2015a) cellophane strips (Pávai et al 2015b) are well applicable for pH and CO 2 sensing.…”

“…The novelties of the sensitive (comparing to the bare eye checking) smartphone camera based method (comparing to the test strips presented in our previous paper (Pávai et al 2015a)) are the real time monitoring option of the pH changes; development a new type of curcumindotted cellophane test strip, that allows multiple sample analyses simultaneously; the preparation of long time stable curcumin-coloured gelatine capsules, applicable more easier at cattering, mobile vendors or households. Schematic illustration of colour determination by the camera of the smartphone is presented on Fig.…”

“…7 shows the grabbed colours on the curcumin dotted cellophane array referring to the different pH standard solutions. Detailed description of the validation process can be found in our previous paper (Pávai et al 2015a). Due to the continuous change of the external light, in the case of a smartphone tester calibration is needed for each measurement (colour grabbing of the dotted cellophane test strip or the dried curcumin-coloured gelatine capsules)…”

A pH-Sensing Film from Tamarind Seed Polysaccharide with Litmus Lichen Extract as an Indicator

“…However, these synthetic chemical dyes may contaminate the food and pose a threat to human health owing to their potential toxicity [ 18 ]. Recently, several studies have reported the potential use of natural pH-sensing dyes such as curcumin and anthocyanin, which are extracted from plants, in intelligent food packaging films [ 2 , 12 , 19 , 20 ]. Natural dyes have more obvious advantages, including nontoxicity, easy preparation, renewability, and a non-polluting nature [ 21 ].…”

Fluorescent microspheres lateral flow assay for sensitive detection of the milk allergen casein

“…However, these methods require expensive equipment, professional operators, and long processing time. Lateral flow immunoassay (LFA) is a screening method used for on-site testing owing to its advantages of convenience (Pávai, Mihály, & Paszternák, 2015;Wu, Liu, et al, 2016), sensitivity, and speed. Colloidal gold (CG) nanoparticles are the most commonly used labeling materials to detect various analytes (Lai, Fung, Yang, Renrong, & Xiong, 2009;Wu, Guo, Dong, & Song, 2016).…”