Tributylhexadecylphosphonium Modification Strategy to Construct Gold Nanoprobes for the Detection of Aqueous Cr(III)–Organic Complexes

Abstract

Most metal probes based on gold nanoparticles (AuNPs) are designed for free metal ions in synthetic waters, and very few are applicable in the detection of metal–organic complexes ubiquitous in real water samples. In this study, we proposed a novel colorimetric nanoprobe strategy for complexed Cr­(III) species based on the analyte-induced aggregation of AuNPs, as coated by a cationic surfactant tributylhexadecylphosphonium bromide (THPB) instead of traditional carboxyl modifiers. Such a detection system could be realized via both naked eye and/or UV–vis spectroscopy with detection limits of 8.0 and 0.29 μM, respectively, much lower than its allowable maximum level in industrial effluent as regulated by China EPA (1.5 mg Cr/L, ∼30 μM). The proposed detection system also exhibits high selectivity against various interfering substances including free ions, small organic molecules, and other metal–citrate complexes. The unique hydrolysis and extremely slow decomplexation of Cr­(III) are believed to favor the formation of the specific interaction between Cr­(III)–citrate and THPB-AuNPs, as verified by X-ray photoelectron spectroscopy characterization, thus endowing the nanoprobe with specific discrimination of the complexed Cr­(III) via the aggregation of THPB-AuNPs. Also, the THPB-AuNPs could be stored at room temperature for 30 days and maintain constant detection performance. Moreover, the quantitative detection of Cr­(III)–organic complexes with the background of various real water samples agreed well with that based on inductively coupled plasma atomic emission spectrometry, making it an attractive alternative for on-site detection of authentic samples containing Cr­(III)–organic species.

Highly Electrocatalytic Conversion and Separation of Organometallic Ions to Vapor on an Au-Modified Nickel Foam Cathode: A Classic Application for Mercury Speciation Analysis at the μg/L Level

“…All electrolytic materials are processed to a uniform size (50 × 10 × 2 mm for electrolysis and 10 × 10 × 2 mm for electrochemical tests) and cleaned in ethanol and DIW for 8 and 10 min respectively with ultrasonic assistance. Au and Ag particles were selected as modifiers considering their catalytic properties. , The preparation process of the modified electrode is shown in Figure S2 (Supporting Information), and briefly, the foam electrode is first etched in 6 mol L –1 HCl to remove the possible oxide layer. Then, a three-electrode system composed of a nickel foam electrode (NFE) (working electrode), Ag/AgCl (reference electrode), and Pt wire (auxiliary electrode) is used to precipitate gold or silver by cyclic voltammetry within the window voltage range of 0.2 to −0.6 V for 30 min at a scan rate of 10 mV s –1 .…”

Cationic Surfactant-Mediated Coagulation for Enhanced Removal of Toxic Metal–Organic Complexes: Performance, Mechanism, and Validation

“…Based on the shifts of both N 1s peak and Cr 2p peak, we postulate that the citrate moiety of the Cr(III)−citrate complexes interacts with the positive head group of CTAB through strong electrostatic interactions, weakening the coordination interaction between Cr(III) and citrate. 10,35 To further elucidate the interaction between Cr(III)−citrate and CTAB, Cryo-TEM characterization was carried out to visualize the formation of the Cr(III)−citrate/CTAB complex during coagulation. In either Cr(III)−citrate (Figure 5A) or CTAB solution (Figure 5B), no aggregation sign could be distinguished.…”

“…31−34 Very recently, we developed a new gold nanoprobe by using cationic surfactants as the modifier for selective and ultrasensitive analysis of various Cr(III)−organic complexes in contaminated waters. 35 The unique interaction between the target metal complexes and the cationic surfactant, that is, tributylhexadecylphosphonium bromide (THPB), was revealed to be responsible for such specific recognition in complex matrixes. As inspired by these interesting studies, here, we reported a proof-of-concept coagulation strategy for the elimination of heavy metal complexes via the formation of ternary selfassemblies using cationic surfactants.…”

High‐efficiency fluorescent probe constructed by Cd(II) complex for detecting nitro compounds and antibiotics

“…How to cite this article: Y. Li, X. Tian, J. Zhang, L. Qiu, X. Wang, S. Wu, Y. Zhang, M. Zhu, E. Gao, Appl Organomet Chem 2021, 35 (12), e6414. https:// doi.org/10.1002/aoc.6414…”

“…[10,11] After the organism is taken, about 30%-90% of the intake is excreted from the organism in the form of mother or metabolites. [12] Long-term exposure to the environment usually causes pollution of surface water, groundwater, and drinking water. [13][14][15][16][17][18][19][20][21] The frequent use of antibiotics leads to their continuous input in the environment.…”