Special Issues-10-03-2015

Is your swimming pool clean and safe? Recreational water illness, most commonly in the form of digestive tract illness or skin, ear, or respiratory infections, is often caused by water contamination. The authors present a robust method, using solid-phase extraction and high-resolution mass spectrometry, for monitoring swimming pool water.

When evaluating the performance of mass spectrometers, one needs to consider the best (or most meaningful) figure of merit to use; options include instrument detection limit (IDL) and signal-to-noise ratio (S/N). In the last 15 years, vendor specifications for S/N have increased from 10:1 to greater than 100,000:1. Does that accurately reflect improvements in mass spectrometers? Although there have been many significant changes, the change in S/N specifications has been far greater than the corresponding change in method detection limits (MDL). Under appropriate conditions, S/N is a meaningful standard, but the value of any S/N must be evaluated in context of the chromatography and sample. Factors influencing the validity of vendor S/N specifications are reviewed, and the statistical alternative of IDL is presented as a replacement that is more consistent with regulatory guidelines and a more relevant indicator of instrument performance.

A method based on thermal desorption with gas chromatography–time-of-flight mass spectrometry (GC–TOF-MS) can elucidate how key volatiles vary with the size of the melon pieces. Such analytical information is of value in efforts to improve the quality and safety of ready-to-eat foods.

The US EPA has implemented an exposure research program aimed at conducting drinking water research on methods as part of the Microbiological and Chemical Exposure Assessment. This research is aimed at evaluating the chemical pollutants and their role and levels in which there is an unacceptable risk to either humans or wildlife, as well as evaluating the methodologies currently being used to determine levels of chemical pollutants.

An analytical methodology for the characterization of the primary structure of biotherapeutic proteins using sheathless CE–ESI-MS-MS instrumentation is presented. For the first time, complete sequence coverage can be achieved using a bottom-up proteomic approach from a single analysis of a tryptic digest. In a biosimilarity assessment, a single amino acid substitution was detected.

Click the title above to open the October 2015 issue of Current Trends in Mass Spectrometry, Volume 13, Number 4, in an interactive PDF format.