P1OS.3 - Colorimetric sensor for phosphate ions detection using 2- mercaptoethanesulfonate modified silver nanoplates

17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
Vienna, Austria
P-1 - Optical Sensors
C. Pinyorospathum, P. Rattanarat, O. Chailapakul - Electrochemical and Optical Spectroscopy Center of Excellence (EOSCE), Department of Chemistry, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok (Thailand), W. Siangproh - Department of Chemistry, Faculty of Science, Srinakharinwirot University, Wattana, Bangkok (Thailand)
622 - 622


A new, distinctive, and inexpensive colorimetric sensor for the detection of phosphate ions (Pi) performed on paper-based analytical device (PAD) based on anti-aggregation of 2-mercaptoethanesulfonate (MS) modified silver nanoplates is proposed. An aggregation of MS-AgNPls due to the electrostatic interaction between the negatively charged sulfonate group on MS-AgNPls and europium ions (Eu3+) causes color change. Whereas, the color of MS-AgNPls remains unchanged in the presence of premixed Eu3+ with Pi because the higher binding affinity of Eu3+ has towards Pi leaving the AgNPls dispersed. An apparent color changing from dark violet to pink with the increasing amount of Pi can be observed by naked eyes on PAD and can be used for quantification by the measurement of color intensity using ImageJ software. The aggregation and anti-aggregation of MSAgNPls were characterized by TEM and UV-visible spectroscopy to confirm the mechanism. This method can detect Pi in the range of 5 - 150 ppm with a detection limit of 1.67 ppm (3 SD/Slope) and a limit of quantification equals to 5.07 ppm (10 SD/Slope). The optimum parameters including pH, concentration of MS and Eu3+, reaction time, and effects of interferences were studied. This method can be applied with the detection of Pi in real samples collecting from soils and in agree with the
standard method (UV-visible spectrophotometry).