Bulk synthesis of conductive non-metallic carbon nanospheres and a 3D printed carrier device for scanning electron microscope calibration.

Herein, a facile method is proposed for the bulk synthesis of conductive non-metallic carbon nanospheres with controllable morphology to replace conventional metal calibration reference materials (CRMs), such as gold nanoparticles and copper grids. The prepared nanospheres had an average diameter of ∼222 ± 23 nm, where silicon dioxide formed the core and the shell was comprised of the carbon layer. The structure of the conductive carbon nanospheres was characterized using FTIR, SEM, EDS and TEM. Additionally, an innovative design was demonstrated by 3D printing the calibration carrier device. Furthermore, the stability and image linear distortion of the conductive carbon nanospheres were verified using analysis of variance (ANOVA). The results demonstrated that the accelerating voltage, magnification, and various positions in the X/Y axes had no significant effect on measured diameter of nanospheres, which was evident from all the p values being greater than 0.05. The comprehensive set of results reveal that conductive carbon nanospheres have great potential to replace traditional CRMs.

Ultrasensitive determination and non-chromatographic speciation of inorganic arsenic in foods and water by photochemical vapor generation-ICPMS using CdS/MIL-100(Fe) as adsorbent and photocatalyst.

The determination of inorganic arsenic species in real samples can be particularly challenging due to their trace levels and the interferences arising from sample matrix. Normally, the speciation analysis necessitates chromatographic separation. Herein, we report a novel method for the ultrasensitive detection and non-chromatographic speciation of inorganic arsenic by inductively coupled plasma mass spectrometry (ICP-MS), utilizing CdS/MIL-100(Fe) composites as an adsorbent and photocatalyst. The synthesized CdS/MIL-100(Fe) could completely adsorb As(V) and As(III) within 5 and 105 min, respectively. Following filtration and re-suspension in formic acid, the adsorbed As(III)/As(V) were reduced to arsine (AsH3) under UV irradiation and swept to ICP-MS for detection. The limits of detection were found to be 1.7 ng L-1 (without preconcentration) and 0.11 ng L-1 (after 20-fold preconcentration). The method was successfully applied to the determination of trace inorganic arsenic in various food and water samples.