Closed-loop stripping

In general terss, the purge-and-trap technique is the nethod of choice Cor detemining organic volatiles in water because of its ease of operation. If greater sensitivity is required, the closed loop stripping apparatus should be used. 

B Closed-Loop Stripping, GC/MS Analysis (Constituent Concentration by Gas Extraction)... 

Melton RG, Coleman WE, Slater RW, et al. 1981. Comparison of Grob closed-loop stripping analysis with other trace organic methods. Adv Identif Anal Org Pollut Water 2 597-673. 

Hwang, C. J., Krasner, S. W., and McGuire, M. J. (1984). Determination of subnanogram per liter levels of earth-musty odorants in water by the salted closed-loop stripping method. Environmental Science and Technology 18,535-539. 

A new major aggregation pheromone emitted by the storage mite, Chor-toglyphus arcuatus, was identified as AR, 6R, 8i )-4,6,8-trimethyldecan-2-one. To identify this new pheromone from mites, headspace of undisturbed colonies of storage mites was analyzed by GC-MS by the use of a closed-loop stripping apparatus or solid phase microextraction. The structure was then elucidated by MS, synthesis of authentic samples, and GC on a chiral... 

Rosel I, A., Gomez-Behnehon, J.L, and Grimalt, J.O., Gas Chromatographic-Mass Spectrometric Analysis of Urban-Related Aquatic and Airborne Volatile Organic Compounds Study of the Extracts Obtained by Water Closed-Loop Stripping and Ah Adsorption with Charcoal and Polyurethane Foam, Journal of Chromatography. Biomedical Applications, Vol. 562, p 493-506. 1991. 

Determination of organic contaminants by the Grob closed-loop stripping technique [136]... 

Buszka, P.M., Zaugg, S.D., Werner, M.G. Determination of trace concentrations of volatile organic compounds in ground water using closed-loop stripping. Bull. Environ. Contamin. Toxicol. 45, 507-515 (1990)... 

Meruva, N.K., Penn, J.M., Farthing, D.E. Rapid identification of microbial VOCs from tobacco molds using closed-loop stripping and gas chromatography/time-of-flight mass spectrometry. J. Ind. Microbiol. Biotechnol. 31, 482-488 (2004)... 

For less volatile compounds, closed-loop stripping has been used in which the analytes are collected on a column of activated carbon from which they are then eluted with carbon disulfide. Attention should especially be drawn to an evaluation of this system for a range of analytes (Coleman et al. 1983) and in particular to the conclusion that for quantification, recovery efficiencies must be evaluated using matrices spiked with the analyte of specific interest. 

Purge-and-trap systems for water and sediment samples followed by sorption and desorption. Both open- and closed-loop stripping have been used. 

Coleman, W.E., J.W. Munch, R.W. Slater, R.G. Melon, and F.C. Kopfler. 1983. Optimization of purging efficiency and quantification of organic contaminants from water using a 1-L closed-loop stripping apparatus and computerized capillary column GC/MS. Environ. Sci. Technol. 17 571-576. 

Foreman, W.T., S.D. Zaugg, L.M. Faires, M.G. Werner, T.J. Leiker, and P.F. Rogerson. 1992. Analytical interferences of mercuric chloride preservative in environmental water samples determination of organic compounds isolated by continuous liquid-liquid extraction or closed-loop stripping. Environ. Sci. Technol. 26 1307-1312. 

Dynamic headspace isolation is a relatively mild method and can be carried out in a relatively short time. With thermal desorption it can be used for a wide range of compound volatilities. However, thermal desorption can also cause molecular clmges to sensitive molecules. Solvent desorption is milder and applicable to large traps but has the same drawback as the other methods which use solvent in that very volatile compounds are lost or obscured. The use of closed loop stripping and binding of water with excess Na2S04 markedly increases the effectiveness of high flow dynamic headspace isolation for very water soluble volatiles. 

Grob, K., Grob, K., Jr. and Grob, G., 1975. Organic substances in potable water and in its precursor. Part III. The closed-loop stripping procedure compared with rapid liquid extraction. J. Chromatogr., 106 299—315. 

Glaze, W. H., M. Koga, E. C. Ruth, and D. Cancilla. 1988. Application of closed loop stripping and XAD resin adsorption for the determination of ozone byproducts from natural water. In Larson, R. A., Ed. Biohazards of Drinking Water Treatment. (Chelsea, MI Lewis Pub.), pp. 201-210. 

Both purge/trap and closed loop stripping (CLS) are varia-... 

Grob. K., Grob, Jr., K., Grob, G. Organic Substances in Potable Water and in its Precursor. Part III. The Closed-Loop Stripping Procedure Compared with Rapid Liquid Extraction, J. of Chromatogr. 109, 299 (197 ... 

Coleman, W. E., Munch, J. W., Slater, R. W., Melton, R. G, Kopfler, F. C. Optimization of Purging Efficiency and Quantification of Organic Contaminants from Water Using a 1-L Closed-Loop-Stripping Apparatus and Computerized Capillary Column GC/MS, Environ. Sci. Technol. 17, 571 (1983)... 

This observation led us to examine whether Arabidopsis flowers emit terpene volatiles. However, standard volatile collection and analysis techniques did not result in readily detectable levels of terpenes. We, therefore, adapted a closed loop stripping method developed initially by Donath and Boland for the detection of Arabidopsis volatiles. This method (Fig. 1.3A) is based on a continuous circulation of air in the headspace of whole plants or plant parts placed in a 1-3 liter glass bell... 

Figure 1.3 Dynamic head space sampling systems for volatile collection. A Closed-loop stripping system according to Donath and Boland, B Semi-open collection system. The direction of the air flow is indicated by arrows.

---