A static headspace method of sampling coupled to a conventional instrumental analytical probe, gas chromatography mass spectrometry (GCMS), has been applied examine the volatile fraction above leaf tissue from Palicourea marcgravii, toxic Brazilian plant that causes sudden death in livestock, and two other surrogate species (Lippia alba Plectranthus spp.). 
 The unusual total ion chromatog...

Optical cavity enhancement is a highly desirable process to make sensitive direct-absorption spectroscopic measurements of unknown substances, such as explosives, illicit material, or other species of interest. This paper reports advancements in the development of real-time cavity ringdown spectroscopy over a wide-bandwidth, with the aim to make headspace measurements of molecules at trace leve...

Solid phase microextraction (SPME) is a popular sampling technique whereby analytes are sorbed to a coated fiber and subsequently desorbed into an analytical instrument. In headspace SPME, analytes partition between the sample, the headspace above the sample, and the SPME fiber coating. In total vaporization SPME (TV-SPME), sample extracts are heated until both the solvent and analytes complete...

An experiment was conducted to investigate the effects of reducing dietary CP and increasing dietary cellulose concentrations on manure DM, C, N, S, VFA, indole, and phenol concentrations. Twenty-two pigs (105 kg initial BW) were fed diets containing either 14.5 or 12.0% CP, in combination with either 2.5 or 8.7% cellulose. Pigs were fed twice daily over the 56-d study, with feed intake averagi...

BACKGROUND The adolescent and early adult years are periods of peak prevalence and incidence for most mental disorders. Despite the rapid expansion of Web-based mental health care, and increasing evidence of its effectiveness, there is little research investigating the characteristics of young people who access Web-based mental health care. headspace, Australia's national youth mental health fo...

dracocephalum kotschyi (lamiaceae), as one of the remarkable aromatic plants, widely grows and also is cultivated in various temperate regions of iran. there are diverse reports about the composition of the oil of this plant representing limonene derivatives as its major compounds. there is no report on cloning of mono- or sesquiterpene synthases from this plant. in the present study, the aroma...

The state of the art of analytical procedures based on solid-phase microextraction (SPME) and its applications to tin, mercury, arsenic, antimony, chromium, selenium, and lead determination in abiotic and biotic matrixes are critically reviewed from 1994 to present. First, sample pretreatment prior to SPME is evaluated, including a description of the most usual leaching procedures for sediment,...

A rapid and simple method of using solid-phase microextraction was developed for determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in water samples. In this method, the target analyte is extracted from the sample into the polymeric coating of the fused-silica fiber. After exposure, the fiber is thermally desorbed in the heated injection port of the gas chromatograph, and a chr...