DFT study of N′-acetyl formohydrazide isomers

Ultraviolet spectra determination and computational analysis of 44 E/Z steroid isomers in dried blood spot

The dried blood spot (DBS) is a novel alternative matrix used in 2022 Beijing Winter Olympics and Paralympics. It is capable of distinguishing anabolic androgenic steroid (AAS) esters without the gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) confirmation. In this study, a method for detection of 22 anabolic steroid esters in DBS based on ultra-high liquid chromatography-mass spectrometry (UPLC-MS) with parallel reaction monitoring (PRM) was developed and validated. Methoxylamine was used as the derivatization reagent to improve the sensibility. Specificity, limit of detection (LOD), linearity, stability, robustness, and carryover were evaluated. Steroid esters are nine testosterone esters, six nandrolone esters, five boldenone esters, methenolone enanthate, and trenbolone acetate. UV spectra were determined by HPLC. And density functional theory (DFT) calculation methods could provide theoretical UV spectra data. Three basis set of B3LYP/6-31G(d), B3LYP/6-31+G(d, p), and WB97XD/6-31+G(d, p) were used for the geometry optimizations and TD-DFT calculation. The average deviation (%RD) of B3LYP/6-31+G(d) for all 44 ester oximes are less than 3.0%. This study for the first time provides a method to tentatively identify the 44 E/Z configurations of steroid oxime products.

An exceptional functionalization of doped fullerene observed via theoretical studies on the interactions of sulfur-doped fullerenes with halogens and halides

Interactions of sulfur-doped fullerenes with halogens and halides have been explored for possible applications such as sensor fabrication and adsorption processes.