Kanagaraj, Rajalakshmi Nam, Yun-Sik Pai, Sung Jin Han, Sang Soo Lee, Kang-Bong 2024-01-20T00:04:02Z 2024-01-20T00:04:02Z 2021-09-03 2017-11 0925-4005 https://pubs.kist.re.kr/handle/201004/122101 Gold nanoparticles (AuNPs) of various sizes were synthesized by modifying the citrate concentration; 45 nm AuNPs were found to respond to Cr6+ ions selectively. Label-free AuNPs, 45 nm, showed localized surface plasmon resonance bands at 530 nm, which decreased linearly upon addition of Cr6+. The addition of Cr6+ also resulted in the appearance of a new band at 750 nm, along with a visible color change in the solution from wine red to violet. The decrease in absorbance and color change were due to AuNP aggregation upon coordination of Cr6+. The detection limit for Cr6+ was 0.4 nM, and excellent selectivity was observed in the presence of other metal ions and anions. The binding site and sensing mechanism for Cr6+ and label-free AuNPs were characterized by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. This method was applied to tap, pond, and waste water samples, and validated using inductively coupled plasma-optical emission spectrometry, illustrating the utility of thes ensitive, selective, and simple AuNP sensor in the detection of Cr6+. (C) 2017 Elsevier B. V. All rights reserved. English ELSEVIER SCIENCE SA COLORIMETRIC DETECTION CHROMIUM CR(VI) SPECTROMETRY SAMPLES WATER Highly selective and sensitive detection of Cr6+ ions using size-specific label-free gold nanoparticles Article 10.1016/j.snb.2017.05.089 1 SENSORS AND ACTUATORS B-CHEMICAL, v.251, pp.683 - 691 SENSORS AND ACTUATORS B-CHEMICAL 251 683 691 scie scopus 000406184600083 2-s2.0-85019994324 Chemistry, Analytical Electrochemistry Instruments & Instrumentation Chemistry Electrochemistry Instruments & Instrumentation Article COLORIMETRIC DETECTION CHROMIUM CR(VI) SPECTROMETRY SAMPLES WATER Label-free AuNPs Colorimetric AuNPs sensor Size-specific nanoparticles Selective Cr6+ detection DFT calculation