Hater samples

Freeze Conceit tret ion Hater sample is partially frozen, concentrating the dissolved substances in the unfrozen portion. All sample types Minimizes sample losses due to volatilization or chemical modification. Principal losses occur due to occlusion, adsorption, evaporation and channelling in the ice layer. Limited sample size. 

Lyophillzation Hater sample is frozen and pure water is removed by sublimation under vacuum. Nonvolatile organics Can handle large sample volumes. Selective loss of volatile organics. Inorganic constituents concentrated simultaneously. 

Surface Adsorption Hater sample is passed through a column of the adsorbent and the adsorbed organic constituents subsequently eluted with a smaller volume of organic solvent. All sample types Adsorbents Include charcoal, macroretlcular resins, polyurethane foams, bonded phases and ion-exchangers. Generally have high capacity but sample discrimination may be a -problem. Sample modification and Incomplete recovery are further possible problems. 

I. H. Suffet and M. Malalyandi, (Eds.), "Organic Pollutants in Hater. Sampling, Analysis, and Toxicity Testing", American Chemical Society, Washington, D.C., 1987. 

Hater samples were processed in the field using a portable water extractor consisting of a stirring blade operated by a battery powered reversible drill which fits into the 20 liter glass carboy (10). The extraction procedure consisted of placing 10 to 15 liters... 

Vacuum Distillation Hater is evaporated at reduced pressure and at or near ambient temperature. Nonvolatile organics Slow process when sample volumes are large. Inorganics also concentrated. Sample contamination is low but sample may be modified due to thermal degradation or chemical and microbial reactions. 

Reverse Osmosis Hater is forced through a membrane by application of pressure thereby enriching the water sample in constituents which ordinarily cannot pass through the membrane. Molecular weight > 200 Compounds of small size are not concentrated. Inorganic materials may contaminate sample. Membranes may either adsorb constituents or release impurities into the sample. 

The as-synthesized TPA[si]-MFI sample appears to be slightly more stable than the aluminium-containing TPA si, Al] -MFI sample. This result is in agreement Hith the semi-empirical calculations of Ooms et al. (12) which show that in the absence of Hater, the aluminium-rich samples are less stable than the purely siliceous ones. HoHever the observed difference betneen the AfH° values is small because the aluminium content of the TPA Si, Al] -MFI sample is not very high (Si/Al = 31). 

H. H. S. V. = 0.4). The activity of the same sample Hhich Has first de-fluorinated and recalcined, decreased more rapidly oning to strong and rapid coking on the acid sites Hhich Here available from the outset. In contrast, in the case of the non-defluorinated sample, the formation of Hater during the conversion leads to the gradual elimination of F and thus makes the acid sites slonly available. 

Hater vapor atmosphere ( p/po = 0.80). The three other calcined samples are hydrophobic. 

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