Highly selective and sensitive paper-based colorimetric sensor using thiosulfate catalytic etching of silver nanoplates for trace determination of copper ions.
A novel, highly selective and sensitive paper-based colorimetric sensor for trace determination of copper (Cu(2+)) ions was developed. The measurement is based on the catalytic etching of silver nanoplates (AgNPls) by thiosulfate (S2O3(2-)). Upon the addition of Cu(2+) to the ammonium buffer at pH 11, the absorption peak intensity of AuNPls/S2O3(2-) at 522 nm decreased and the pinkish violet AuNPls became clear in color as visible to the naked eye. This assay provides highly sensitive and selective detection of Cu(2+) over other metal ions (K(+), Cr(3+), Cd(2+), Zn(2+), As(3+), Mn(2+), Co(2+), Pb(2+), Al(3+), Ni(2+), Fe(3+), Mg(2+), Hg(2+) and Bi(3+)). A paper-based colorimetric sensor was then developed for the simple and rapid determination of Cu(2+) using the catalytic etching of AgNPls. Under optimized conditions, the modified AgNPls coated at the test zone of the devices immediately changes in color in the presence of Cu(2+). The limit of detection (LOD) was found to be 1.0 ng mL(-1) by visual detection. For semi-quantitative measurement with image processing, the method detected Cu(2+) in the range of 0.5-200 ng mL(-1)(R(2)=0.9974) with an LOD of 0.3 ng mL(-1). The proposed method was successfully applied to detect Cu(2+) in the wide range of real samples including water, food, and blood. The results were in good agreement according to a paired t-test with results from inductively coupled plasma-optical emission spectrometry (ICP-OES).
Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand.
Sudkate
S
Chaiyo
Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Wattanna, Bangkok 10110, Thailand.
Weena
W
Siangproh
Center for Innovation Development and Technology Transfer, Faculty of Medical Technology, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170, Thailand. Electronic address: amara.apl@mahidol.ac.th.
Amara
A
Apilux
Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand; Center for Petroleum, Petrochemicals and Advanced Materials, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand. Electronic address: corawon@chula.ac.th.
Orawon
O
Chailapakul
D000641:Ammonia / Q000737:chemistry; D001628:Beverages / Q000032:analysis; D002384:Catalysis; D003124:Colorimetry; D003300:Copper / Q000032:analysis*; D005504:Food Analysis; D005618:Fresh Water / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D010209:Paper; D012834:Silver / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013885:Thiosulfates / Q000737:chemistry*
D007477:Ions; D008670:Metals; D013885:Thiosulfates; D012834:Silver; D000641:Ammonia; D003300:Copper
Colorimetric detection; Copper ions; Paper-based sensor; Silver nanoplates; Thiosulfate