Tips & Tricks: Aqueous GPC/SEC: Influence of Salt and pH
June 1st 2018While gel permeation chromatography/size-exclusion chromatography (GPC/SEC) of uncharged molecules in organic eluents in most cases is a straightforward task, aqueous GPC/SEC of polyelectrolytes usually requires more parameters to be considered and optimized. This instalment of Tips & Tricks explains more.
Resources for Careers in Metabolomics for Early Career Researchers
June 1st 2018Metabolomics, a word coined in 1998, is the study of small molecules (that is, organic chemicals with a molecular weight of 50–2000 Daltons) present in a given biological fluid, tissue, organ, organism, and environment at a given time. Using the power and high throughput of analytical platforms, such as mass spectrometry (MS) or nuclear magnetic resonance (NMR) spectroscopy, metabolomics promises to be a cornerstone in innovations and discoveries in the areas of medicine, agriculture, biomedical, space, and environment. Thus, science, technology, engineering, and mathematics (STEM) graduates and doctorates who interface with analytical chemistry need to prepare for the challenges of academia or industry as metabolomics research takes a centre stage in this big data era.
Injecting Water onto a GC Column: Solving the Mystery of Poor Chromatography
June 1st 2018Ethylene glycol is a particularly difficult compound to analyze because it is not easily extracted from water. Many environmental samples originate from water runoff at airports, where ethylene glycol is used as a de‑icing agent for airplanes during winter months. Hydraulic fracturing is a technique where pressurized fluid and sand or other solids (proppant) are used in gas drilling to allow gas extraction. Glycols are a common ingredient in most hydraulic fracturing fluid and play a key role in preventing emulsifications and stabilizing the solutions. The direct aqueous injection of ethylene glycol is challenging because it can be difficult to attain reproducibility and good peak shape. The large expansion volume of water can cause backflash, carryover can cause inconsistent results, and excess water can extinguish the flame ionization detection (FID) flame. This article describes a robust approach to analyze glycols in aqueous samples, which reduces downtime and maintains sensitivity.