Specific and sensitive colorimetric detection of Al3+ using 5-mercaptomethyltetrazole capped gold nanoparticles in aqueous solution

• Published in: Talanta (Oxford) Vol. 119; pp. 306 - 311
• Main Authors: Xue, Dingshuai, Wang, Hongyue, Zhang, Yanbin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-02-2014
• Subjects: 5-mercaptomethyltetrazole; Agglomeration; Al3; Aluminum - analysis; Anions; Aqueous solutions; Assaying; Colorimetric detection; Colorimetry; Crosslinking; Drinking water; Gold; Gold - chemistry; Gold nanoparticles; Limit of Detection; Metal Nanoparticles; Microscopy, Electron, Transmission; Solutions; Spectrum Analysis, Raman; Sulfhydryl Compounds - chemistry; Tetrazoles - chemistry; Water - chemistry; Al3; 5-mercaptomethyltetrazole; Gold nanoparticles; Colorimetric detection; Al(3+)
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2013.11.012

Contamination of food and drinking water by health-risk levels of Al3+ calls for convenient assays. Here, we report a method to visibly detect Al3+ at room temperature. Firstly, the chelating ligand of 5-mercaptomethyltetrazole (MMT) was synthesized and modified on the surface of AuNPs through the strong Au–S interaction to form a MMT–AuNP probe, which can remain well-dispersed and stable in an aqueous solution for a long time. Upon the addition of Al3+, the interparticle crosslinking induced aggregation (color change from red to blue) of MMT–AuNPs was triggered through the Al3+–MMT interaction. Under optimal conditions, the absorbance ratio (A620/A520) of MMT–AuNPs is linear within the Al3+ concentration range from 1.0 to 10.0μM, and the detection limit (3σ) was as low as 0.53μM. Moreover, an interference study showed that this MMT–AuNP probe discriminated Al3+ from a wide range of environmentally dominant metal ions and anions. The practical utility of the new method was demonstrated by determining Al3+ in several environmental water and human urine specimens, obtaining satisfactory results. Being a rapid, convenient and cost-effective method, it should become a powerful alternative to conventional methods for selective quantification of Al3+ in routine laboratory practice or rapid on-site assay.
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•We synthesized 5-mercaptomethyltetrazole (MMT) and used it as a complex ligand to modify gold nanoparticles (MMT–AuNPs).•The MMT–AuNPs exhibited well-dispersed and stable properties in aqueous solution.•The Al3+ addition induced aggregation of MMT–AuNPs gives rise to significant color change from red to blue.•The distinct color change facilitates visual detection of Al3+ and the detection limit (3σ) is as low as 0.53μM.•The MMT–AuNPs probe could be successfully applied for sensing Al3+ in complex media such as urine samples.