title: Highly sensitive colorimetric detection of lead using maleic acid functionalized gold nanoparticles.
abstract: Highly sensitive colorimetric detection for Pb(2+) has been developed using maleic acid (MA) functionalized GNP. The -COOH on MA was used to modify GNP surface whereas the other -COOH functional group have strong affinity to coordination behavior of Pb(2+) allowing the selective formation more than other ions. MA-GNPs solution changed from red to blue color after the addition of Pb(2+) due to nanoparticle aggregation. The different optical absorption and discriminate of particle size between the MA-GNPs solution with and without Pb(2+) were characterized by UV-visible spectroscopy and transmission electron microscopy (TEM), respectively. The color intensity as a function of Pb(2+) concentration gave a linear response in the range of 0.0-10.0 µg L(-1) (R(2)=0.990). The detection limit was found at 0.5 µg L(-1) by naked eye and can be completed the analysis within 15 min. The MA-GNPs aggregated with Pb(2+) showed high selectivity when was compared to other metal ions (As(3+), Ca(2+), Cd(2+), Co(2+), Cu(2+), Fe(3+), Hg(2+), Mg(2+), Mn(2+), Ni(2+), Pb(2+) and Zn(2+)) and anions (Cl(-), NO3(-) and SO4(2-)). Our proposed method was also applied for the determination of Pb(2+) in real drinking water samples from 5 sources. The result of real water samples were not statistically significant different from the standard methods at the 95% confidence level (pair t-test method). Moreover, we evaluated our proposed method for the determination of trace Pb(2+) concentration in real breast milk samples. The recoveries were acceptable and ranged from 101 to 104% for spiked Pb(2+) in real breast milk samples. Thus, MA-GNP colorimetric sensing provides a simple, rapid, sensitive, easy-to-use, inexpensive and low detection limit for the monitoring of Pb(2+).
authors.affiliation: Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi, Prachautid Road, Thungkru, Bangkok 10140, Thailand.
authors.forename: Nalin
authors.initials: N
authors.lastname: Ratnarathorn
authors.affiliation: Center of Excellence for Petroleum, Petrochemicals, and Advanced Materials, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand.
authors.forename: Orawon
authors.initials: O
authors.lastname: Chailapakul
authors.affiliation: Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi, Prachautid Road, Thungkru, Bangkok 10140, Thailand. Electronic address: wijitar.dun@kmutt.ac.th.
authors.forename: Wijitar
authors.initials: W
authors.lastname: Dungchai
mesh_terms: D002413:Cations, Divalent; D003124:Colorimetry / Q000379:methods*; D056831:Coordination Complexes / Q000737:chemistry; D060766:Drinking Water / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007854:Lead / Q000032:analysis*; D057230:Limit of Detection; D008298:Maleates / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D008895:Milk, Human / Q000737:chemistry*
chemical_list: D002413:Cations, Divalent; D056831:Coordination Complexes; D060766:Drinking Water; D008298:Maleates; D007854:Lead; D006046:Gold; C030272:maleic acid
keywords: Colorimetric sensing; Gold nanoparticles; Lead