8 research outputs found
GC × GC–HRMS nontarget fingerprinting of organic micropollutants in urban freshwater sediments
Nontarget Screening of Complex Environmental Matrices:From Sampling to Compound Identification – The Development of Complementary Analytical Platforms
Supercritical fluid chromatography for the analysis of oxygenated polycyclic aromatic compounds in unconventional oils
Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments from Khuzestan province, Iran
Nontarget Analysis of Oxygenates in Catalytic Fast Pyrolysis Biocrudes by Supercritical Fluid Chromatography High-Resolution Mass Spectrometry
Catalytic
fast pyrolysis (CFP) biocrudes can comprise up to 30
wt % of oxygen content in compounds such as polyphenols, acids, carbonyls,
and anhydrosugars and thus require upgrading by, e.g., hydrotreatment,
to produce transport fuels. The chemical characterization of phenolic
and acidic compounds in biocrudes is of great importance to optimize
the CFP process. In this study, an analytical workflow is proposed
for nontarget chemical fingerprinting analysis of CFP biocrudes using
supercritical fluid chromatography high-resolution mass spectrometry
(SFC-HRMS) with negative electrospray ionization (ESI–), followed by multivariate data analysis. The method was developed
and tested on five biocrude samples from loblolly pine (Pinus taeda) with varying oxygen content (14.9–28.8
wt % wet basis) due to different CFP conditions. The pixel-based analysis
displayed chemical variation between all samples. Twenty-four regions
of interest were tentatively identified, including mono- and polyphenols,
fatty acids, and methylated and methoxylated phenols. The identification
workflow and MS/MS analysis were prioritized on the peaks with the
highest relative concentration. The developed SFC-ESI–-HRMS method shows high repeatability and analyzed oxygen-containing
compounds with hydroxyl and/or carboxyl moieties in combination with
other moieties of up to 400 Da
Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments from Khuzestan province, Iran
Oxygen targets and 6-month outcome after out of hospital cardiac arrest: a pre-planned sub-analysis of the targeted hypothermia versus targeted normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial
International audienceAbstract Background Optimal oxygen targets in patients resuscitated after cardiac arrest are uncertain. The primary aim of this study was to describe the values of partial pressure of oxygen values (PaO 2 ) and the episodes of hypoxemia and hyperoxemia occurring within the first 72 h of mechanical ventilation in out of hospital cardiac arrest (OHCA) patients. The secondary aim was to evaluate the association of PaO 2 with patients’ outcome. Methods Preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after OHCA (TTM2) trial. Arterial blood gases values were collected from randomization every 4 h for the first 32 h, and then, every 8 h until day 3. Hypoxemia was defined as PaO 2 300 mmHg. Mortality and poor neurological outcome (defined according to modified Rankin scale) were collected at 6 months. Results 1418 patients were included in the analysis. The mean age was 64 ± 14 years, and 292 patients (20.6%) were female. 24.9% of patients had at least one episode of hypoxemia, and 7.6% of patients had at least one episode of severe hyperoxemia. Both hypoxemia and hyperoxemia were independently associated with 6-month mortality, but not with poor neurological outcome. The best cutoff point associated with 6-month mortality for hypoxemia was 69 mmHg (Risk Ratio, RR = 1.009, 95% CI 0.93–1.09), and for hyperoxemia was 195 mmHg (RR = 1.006, 95% CI 0.95–1.06). The time exposure, i.e., the area under the curve (PaO 2 -AUC), for hyperoxemia was significantly associated with mortality ( p = 0.003). Conclusions In OHCA patients, both hypoxemia and hyperoxemia are associated with 6-months mortality, with an effect mediated by the timing exposure to high values of oxygen. Precise titration of oxygen levels should be considered in this group of patients. Trial registration : clinicaltrials.gov NCT02908308 , Registered September 20, 2016