Gas stripping, sorption, and thermal desorption procedures for preconcentrating volatile polar water-soluble organics from water samples for analysis by gas chromatography

Abstract

the samples being analyzed, by making up standards in a synthetic matrix similar to the average major composition of the materials being analyzed, or by using either of the previous methods and buffering samples and standards by dissolving in them a fairly large amount of an element with a low ionization potential, such as potassium or lithium (16,26).Applicability to Other Elements. Without any further sample preparation, the spectrometer/spectrograph was employed to estimate the major compositions of IAEA S-5 and Kieselguhr which are included in Table VII. The synthetic blank solution and the solutions of NBS-91, VS-N, NBS 613, and GSB were used as calibration standards in these determinations. This same approach was used to estimate concentrations of iron and copper in three samples of diatom ash. The results of these analyses are included in Table IV.A detailed consideration of the use of the dc argon plasma jet to perform multielement emission spectrometric analyses of siliceous materials of diverse major compositions will be presented elsewhere.ACKNOWLEDGMENT We thank V. T. Bowen and R. R. L. Guillard for helpful suggestions, .

Solid-phase Microextraction of Volatile Polar Compounds in Water

“…Purge-and-trap methods generally detect lower levels because there is a tendency to transfer the entire amount in the sample to GC for a single analysis. For hydrophilic organic compounds (in water [24], biological fluids [25]) the purging efficiency increases with increasing temperature (up to 90 8C [25], 95 8C [24]) and long stripping procedures have been utilized (15 min -1 h). However, this in turn causes increased water vapor levels in the stripping gas.…”

“…However, this in turn causes increased water vapor levels in the stripping gas. It is possible to analyze ppb levels of volatile polar compounds in a water matrix, with the recoveries varying from, e.g., 9.5% for ethanol from water [24] to 98.4% for tert-butyl alcohol from human urine [25].…”

Literature Review and Evaluation of Solid Sorbents for Water Sampling of Explosives

“…Brown and Purnell (1979) claim that breakthrough on Tenax GC is affected by vapor concentration, but that humidity appears to have no affect on retention volumes. Kuo et al (1977) used Tenax GC as a sorbent for water soluble organics which were gas-purged from * water.…”

Elemental Analysis

“…Direct methods of analysis such as distillation [158,167,168], liquid-liquid extraction [159,169], headspace analysis [170][171][172], dynamic headspace analysis [157,[173][174][175][176][177][178], and direct injection [179] have been used mainly for specific volatile components.…”

“…The efficiency of extraction can be increased by using a purging gas and increasing the temperature of the sample to 60-80 • C [173]. The efficiency and properties of Tenax GC have been examined [177,[185][186][187].…”