Akademik Veri Yönetim Sistemi
Microchemical Journal, cilt.222, 2026 (SCI-Expanded, Scopus)
Pentaerythritol tetranitrate (PETN) is a nitrate ester explosive used as an energetic and filling material for military and civilian purposes, and unfortunately, in terrorist activities. Spectroscopic studies reported in the literature for the determination of PETN lack a direct determination method, meaning that PETN is usually detected after hydrolytic cleavage to nitrite or nitrate. Here, a direct colorimetric nanoprobe based on gold nanoparticle aggregation and incorporating a π–hole interaction mechanism was designed for the selective, sensitive, and direct determination of intact PETN. The nanoprobe (AuNPs@2NT) was synthesized by modifying the surface of nanogold with 2–naphthalenethiol (2NT). Using an innovative approach, a π–hole interaction occurs between the nitro group of PETN and the aromatic ring of 2NT, and the presence of four nitro groups in the PETN molecule causes the aggregation of several AuNPs@2NT, owing to the potent and directional π-hole character of the nitrate ester. The analytical signal obtained as a result of aggregation can be monitored both with the naked–eye and by UV–vis spectrophotometry, and the detection limit (LOD) of AuNPs@2NT for PETN is 1.62 nmol L−1. AuNPs@2NT, which exhibits high selectivity for PETN among different explosives, can determine PETN with high recoveries (93.9%–106.3%) even in the presence of potentially interfering species, such as the trinitro-explosive TNT. While PETN has four discrete aliphatic nitro-groups (that are not coplanar) capable of π-hole interaction with several AuNPs@2NT forming clusters, the coplanar nitro-groups of TNT and other nitro-explosives, including mono- and di-nitrate esters, cannot perform the same task. This mechanism of detection is completely novel for PETN, ensuring analytical selectivity. The hydrogel support material (Au–gel) developed for the practical application of the nanoprobe can retain the nanoparticles in its structure and allows the aggregation of AuNPs@2NT upon interaction with the PETN solution. Thus, the red colored Au–gel turns purple upon interaction with PETN, and this signal change can be successfully monitored via a smartphone application.