Renee N. Easter

Separation and identification of oligonucleotides by hydrophilic interaction liquid chromatography (HILIC)—inductively coupled plasma mass spectrometry (ICPMS)

A method for the separation and detection of oligonucleotides utilizing hydrophilic interaction liquid chromatography (HILIC) with inductively coupled plasma mass spectrometry (ICPMS) is described. Polythymidylic acids of various lengths (10, 15, 20 and 30 nucleotides) were separated under gradient HILIC conditions. Selective detection of oligonucleotides was possible through monitoring m/z 47, corresponding to (31)P(16)O(+), using ICPMS. Oxygen was used as a reaction gas in the collision/reaction cell to produce PO(+) by reacting with phosphorus in the gas phase, thereby effectively eliminating the interferences for phosphorus normally seen at m/z 31. Limits of detections (LODs) were determined to be 1.69 pmol, 1.21 pmol, 1.0 pmol and 0.55 pmol loaded on column for the 10, 15, 20 and 30 mer, respectively.

Vascular metallomics: Copper in the vasculature

Owing to recent progress in analytical techniques, metallomics are evolving from detecting distinct trace metals in a defined state to monitor the dynamic changes in the abundance and location of trace metals in vitro and in vivo. Vascular metallomics is an emerging field that studies the role of trace metals in vasculature. This review will introduce common metallomics techniques including atomic absorption spectrometry, inductively coupled plasma-atomic emission spectrometry, inductively coupled plasma-mass spectrometry and X-ray fluorescence spectrometry with a summary table to compare these techniques. Moreover, we will summarize recent research findings that have applied these techniques to human population studies in cardiovascular diseases, with a particular emphasis on the role of copper in these diseases. In order to address the issue of interdisciplinary studies between metallomics and vascular biology, we will review the progress of efforts to understand the role of copper in neovascularization. This recent advance in the metallomics field may be a powerful tool to elucidate the signaling pathways and specific biological functions of these trace metals. Finally, we summarize the evidence to support the notion that copper is a dynamic signaling molecule. As a future direction, vascular metallomics studies may lead to the identification of targets for diagnosis and therapy in cardiovascular disease.

Recent developments and novel applications in GC-ICPMS

The objective of this review is to note recent novel developments and applications rather than to be comprehensive. We intend to explore instrumental advances that demonstrate enhanced analytical capability. Along these same lines, there have been a number of recent papers coupling solid phase microextraction with GC-ICPMS and these will be discussed. Not only does this preparation technique present several advantages, such as environmental friendliness through reduced solvent consumption, it also lends itself to easy incorporation into a GC analytical scheme. Finally, new explorations in the analysis of the traditional metal species, as well as novel applications of species of nontraditional elements, are presented.

Separation and identification of phosphorothioate oligonucleotides by HILIC-ESIMS

A combined hydrophilic interaction chromatography (HILIC) electrospray ionization mass spectrometry (ESI-MS) approach for the separation and identification of phosphorothioate oligonucleotides is described. Phosphorothioate 21-mer and 23-mer were separated by HILIC and detected using selected ion monitoring (SIM) ESI-MS. Phosphorothioates could be detected from 50 nM solutions suggesting effectiveness comparable to ion pairing reversed phase chromatography approaches.

Protein phosphorylation studies of cerebral spinal fluid for potential biomarker development

Subarachnoid hemorrhage (SAH) followed by cerebral vasospasm (CV) leads to severe debilitation or death of an estimated one million people worldwide every year. A biomarker that would predict the onset of CV after a SAH would be useful in informing treatment protocols, but has yet to be found. The focus of this study is to explore differences in protein phosphorylation in cerebral spinal fluid (CSF) among healthy patients, SAH patients and SAH-CV patients. A significant difference in phosphorylation among the three sample types could be an important step towards the discovery of a diagnostic marker. The identification and validation of phosphorylated protein differences for study is manifested in the nature of signaling involved in the pathological events seen post SAH. Capillary liquid chromatography (cap-LC) coupled to inductively coupled plasma mass spectrometry (ICPMS) and nano-liquid chromatography-CHIP/ion trap mass spectrometry (nanoLC-CHIP/ITMS) are used to identify and measure protein phosphorylation changes in the CSF of the aforementioned groups. ICPMS represents a suitable method for screening ultra-trace phosphorus levels at the natural isotope, (31)P, while nano-LC-CHIP/ITMS is used to identify phosphoproteins by searching appropriate protein databases.