Tenax™

Phormium. The Phormium tenax plant yields a long, light-colored, hard fiber also known as New Zealand hemp or flax, although it has none of the bast fiber characteristics. The plant is a perennial of the Agavaceae with leaves up to 4 m long and 10 cm wide. The fibers are recovered by mechanical decortication. 

When a comparative analysis of the headspace volatiles of living and picked osmanthus flowers was performed by the dynamic headspace trapping method using Tenax GC, even more dramatic differences were observed, shown in Table 20 (60). 

One example is sampling for S02- Liquid sorbents for SO2 depend on the solubility of SO2 in the liquid collection medium. Certain liquids at the correct pH are capable of removing ambient concentrations of SO2 with 100% efficiency until the characteristics of the solution are altered so that no more SO2 may be dissolved in the volume of liquid provided. Under these circumstances, sampling is 100% efficient for a limited total mass of SO2 transferred to the solution, and the technique is acceptable as long as sampling does not continue beyond the time that the sampling solution is saturated (1). A second example is the use of solid sorbents such as Tenax... 

A solid sorbent Tenax cartridge has a capacity of 100 fig of toluene. If samples were collected at a rate of 5 liters/min, calculate the maximum ambient concentration which can be determined by an hourly sample and a 15-min sample. 

Tenax Various grades for collection of a range of boiling-point compounds. Suitable for low ambient concentrations... 

Lab method using glass-fibre/Tenax tube sampling and high performance liquid chromatography Field method using acid hydrolysis, diazotization, coupling and spectrophotometry... 

Diethyl sulphate and dimethyl sulphate Lab method using Tenax sorbent tube, thermal desorption and gas chromatography with mass spectrometry 89... 

Dioctyl phthalate Lab method using Tenax sorbent tubes, solvent desorption and gas chromatography 32... 

Ethylene dibromide Lab method with pumped Tenax absorbent tubes, solvent desorption and electron capture gas chromatography 45... 

Glycol ether and glycol ether acetate vapours m air (Tenax adsorbent tubes)... 

Figure 14.12 Schematic diagram of the Refomiulyser system Inj, split injector Cl, polar capillary column C2, packed column to retain the alcohols C3, packed Porapak column for the separation of the oxygenates C4, non-polar capillary column C5, packed 13X column A/E cap, Tenax trap to retain the ar omatics Olf. trap, cap to retain the olefins Pt, olefins hydrogenatOT A cap, cap to retain the -alkanes FID, flame-ionization detector.

Laboratory method using porous polymer adsorbent tubes, thermal desorption and gas chromatt raphy MDHS 32 Dioctyl phthalates in air Laboratory method using Tenax adsorbent tubes, solvent desorption and gas chromatography MDHS 33 Adsorbent tu standards Preparation by the syringe loading technique MDHS 34 Arsine in air Colorimetric field method using silver diethyl-dithiocarbamate in the presence of excess silver nitrate... 

Exhaled air Collected on Tenax -GC, thermally desorbed injected into GC HRGC/MS 0.3 ppb 95-99 Wallace et al. 1986a... 

Human milk Purged warm trapped in Tenax(I)-GC thermally desorbed HRGC/MS Qualitative identification NR Pellizzari et al. 1982... 

Purge-and-trap methods have also been used to analyze biological fluids for the presence of trichloroethylene. Breast milk and blood were analyzed for trichloroethylene by purging onto a Tenax gas chromatograph to concentrate the volatiles, followed by thermal desorption and analysis by GC/MS (Antoine et al. 1986 Pellizzari et al. 1982). However, the breast milk analysis was only qualitative, and recoveries appeared to be low for those chemicals analyzed (Pellizzari et al. 1982). Precision (Antoine et al. 1986) and sensitivity (Pellizzari et al. 1982) were comparable to headspace analysis. 

Adsorbed on Tenax -GC thermally desorbed to on-column cold trap heat-released... 

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