title: Chromatic analysis by monitoring unmodified silver nanoparticles reduction on double layer microfluidic paper-based analytical devices for selective and sensitive determination of mercury(II).
abstract: This study demonstrates chromatic analysis based on a simple red green blue (RGB) color model for sensitive and selective determination of mercury(II). The analysis was performed by monitoring the color change of a microfluidic Paper-based Analytical Device (µPAD). The device was fabricated by using alkyl ketene dimer (AKD)-inkjet printing and doped with unmodified silver nanoparticles (AgNPs) which were disintegrated when being exposed to mercury(II). The color intensity was detected by using an apparatus consisting of a digital camera and a homemade light box generating constant light intensity. A progressive increase in color intensity of the tested area on the µPAD (3.0mm) was observed with increasing mercury(II) concentration. The developed system enabled quantification of mercury(II) at low concentration with the detection limit of 0.001mgL(-1) (3 SD blank/slope of the calibration curve) and small sample volume uptake (2µL). The linearity range of the calibration curve in this technique was demonstrated from 0.05 to 7mgL(-1) (r(2)=0.998) with good precision (RSD less than 4.1%). Greater selectivity towards mercury(II) compared with potential interference ions was also observed. Furthermore, the percentage recoveries of spiked water samples were in an acceptable range which was in agreement with the values obtained from the conventional method utilizing cold vapor atomic absorption spectrometer (CVAAS). The proposed technique allows a rapid, simple, sensitive and selective analysis of trace mercury(II) in water samples.
authors.affiliation: Department of Chemistry and Center of Excellent for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand.
authors.forename: Rattapol
authors.initials: R
authors.lastname: Meelapsom
authors.affiliation: Department of Chemistry and Center of Excellent for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand. Electronic address: purim.j@ubu.ac.th.
authors.forename: Purim
authors.initials: P
authors.lastname: Jarujamrus
authors.affiliation: Department of Chemistry and Center of Excellent for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand.
authors.forename: Maliwan
authors.initials: M
authors.lastname: Amatatongchai
authors.affiliation: Department of Chemistry and Center of Excellent for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand.
authors.forename: Sanoe
authors.initials: S
authors.lastname: Chairam
authors.affiliation: Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Chadin
authors.initials: C
authors.lastname: Kulsing
authors.affiliation: Department of Chemical Engineering, Institute, Monash University, Clayton Campus, Melbourne VIC 3800, Australia.
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
keywords: CVAAS; Chromatic analysis; ImageJ; Mercury (Hg(II)); RGB system; Silver nanoparticles (AgNPs)