First case of Desulfovibrio desulfuricans bacteraemia successfully identified using MALDI-TOF MS.

Desulfovibrio species are anaerobic Gram-negative bacilli that make up part of the human gastrointestinal and vaginal flora. Infection with these bacteria is usually secondary to an intra-abdominal source. Identification of these bacteria is possible using available contemporary methods. We report the first case of Desulfovibrio desulfuricans bacteraemia identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).

Experimental performances study of a transportable GC-PID and two thermo-desorption based methods coupled to FID and MS detection to assess BTEX exposure at sub-ppb level in air.

BTEX compounds are of particular interest, above all benzene because it is a carcinogenic compound for which guideline value in European indoor environments is set to be 1.6 ppb. Therefore, the detection of such relatively low value requires the use of particularly sensitive analytical techniques. Several existing chromatographic techniques, such as fast and transportable Gas Chromatograph with Photoionization Detection (GC-PID) or sedentary chromatographic-based techniques equipped with a thermo-desorption device (ATD) and coupled to either Flame Ionization Detection (FID) or Mass Spectrometry (MS), can quantify benzene and its derivatives at such low levels. These instruments involve different injection modes, i.e. on-line gaseous sampling or thermo-desorption of adsorbent tubes spiked with liquid or gas samples. In this study, the performances of 3 various analytical techniques mentioned above were compared in terms of sensitivity, linearity, accuracy and repeatability for the 6 BTEX. They were also discussed related to their analyses time consumption or transportability. The considered analytical techniques are ATD-GC-FID, ATD-GC-MS where both full scan and SIM modes were tested and a transportable GC-PID. For benzene with on-line injection, Limits of Detection (LOD) were significantly below the European guideline with values of 0.085, 0.022, 0.007 and 0.058 ppb for ATD-GC-FID, ATD-GC-MS in a full scan mode, ATD-GC-MS in an SIM mode and transportable GC-PID, respectively. LOD obtained with adsorbent tubes spiked with liquid standards were approximately in the same order of magnitude.