Are matrix isolated species really “isolated”? Infrared spectroscopic and theoretical studies of noble gas-transition metal oxide complexes

In this review, we summarize our recent results on matrix isolation infrared spectroscopic studies and theoretical investigations of noble gas-transition metal oxide complexes. The results show that some transition metal oxide species trapped in solid noble gas matrices are chemically coordinated by one or multiple noble gas atoms forming noble gas complexes and, hence, cannot be regarded as isolated species. Noble gas coordination alters the vibrational frequencies as well as the geometric and electronic structures of transition metal oxide species trapped in solid noble gas matrixes. The interactions between noble gas atoms and transition metal oxides involve ion-induced dipole interactions as well as chemical bonding interactions. Periodic trends in the bonding in these noble gas-transition metal complexes are discussed.

Infrared spectroscopic probing of dimethylamine clusters in an Ar matrix

Amines have many atmospheric sources and their clusters play an important role in aerosol nucleation processes. Clusters of a typical amine, dimethylamine（DMA）, of different sizes were measured with matrix isolation IR（infrared） and NIR（near infrared）spectroscopy. The NIR vibrations are more separated and therefore it is easier to distinguish different sizes of clusters in this region. The DMA clusters, up to DMA tetramer, have been optimized using density functional methods, and the geometries, binding energies and thermodynamic properties of DMA clusters were obtained. The computed frequencies and intensities of NH-stretching vibrations in the DMA clusters were used to interpret the experimental spectra. We have identified the fundamental transitions of the bonded NH-stretching vibration and the first overtone transitions of the bonded and free NH-stretching vibration in the DMA clusters. Based on the changes in vibrational intensities during the annealing processes, the growth of clusters was clearly observed. The results of annealing processes indicate that DMA molecules tend to form larger clusters with lower energies under matrix temperatures, which is also supported by the calculated reaction energies of cluster formation.

Direct Analysis of Whole Blood by a Disposable Monolithic Column Mass Spectrometry Analysis Kit

A monolithic column-based mass spectrometry(MS)analysis kit was prepared for whole blood analysis with MS.The kit is disposable and can be used for purification,storage,transportation and direct analysis of whole blood.The kit mainly consists of a capillary for quantitative microsampling,a cation exchange monolithic column for purification and storage,and a syringe for loading sample.This kit is very friendly to various users that one can easily siphon the blood in the kit followed by rapid clean-up.We established a quantitative method using the kit with a limit detection as low as 0.33 nmol/L,and achieved more than five orders of magnitude enhancement in sensitivity compared to direct nanoelectrospray ionization MS analysis.The column can avoid analyte exposure to environment,which helps the storage of the sample for laboratory analysis.The relative standard deviation of immediate blood analysis and storage blood analysis within 10 d was less than 10%.This method has been successfully applied to the quantitative analysis of procainamide hydrochloride in 2μL rat blood.These results indicate that this disposable kit does have the potential to achieve highly sensitive quantitative MS analysis in biological samples,which is expected to become a cost-effective and powerful tool for in vitro diagnostics.