Bag sampling

Each vegefafion, soil or tissue sample was uniquely numbered and stored individually in a plastic Ziploc bag. Samples were frozen until shipped to laboratory facilities. Samples were shipped in coolers with dry-ice and were returned to freezers immediately upon receipt at the analytical laboratories. Control samples were stored separately from treated samples. 

Ammonium acetate, HPLC grade (Fisher Scientific, Fair Lawn, NJ) or equivalent Bags, sample storage, plastic... 

To prevent dusts from clogging the olfactometer tubes, a glass filter (with low retention of odorous molecules) is set upstream the apparatus. In case of dusts in the analyzed gas, it is better to make a bag sampling without filtering the dusts likely to have trapped the odorous compounds are sedimented in the bag, are not re-suspended when the gas is introduced into the olfactometer, and eventually desorb the odorous compounds in the bag. 

Nonurban oxidant measurements in Ohio were reported by Neligan and Angus. Concentrations of 0.18 and 0.12 ppm were reported for rural sites in Wilmington and McConnelsville, respectively. At the same time, urban sites had similar concentrations. However, the nonurban sites violated the ambient air quality standard more frequently than the urban sites. Trajectory analysis showed that ozone concentrations of 0.04-0.06 ppm were found in air masses that had not passed over anthropogenic hydrocarbon sources. These may have been examples of naturally occurring oxidant. Airborne hydrocarbon bag samples were obtained over 6-min... 

Figure 6 illustrates another highly developed application of our FTIR facility. Trace (A) shows the complete absorbance spectrum, 600-3600 cm-1, of a CVS bag sample of a typical auto exhaust. While dominated by water vapor and CO2 absorption, several interesting features are visible. For instance, the carbon monoxide band is readily apparent, as is absorption due to heavy hydrocarbon (indicated by the broad unresolved C-H stretch band). In Trace (B) absorption due to CH4, NO2, formaldehyde and as well, water and heavy hydrocarbon can clearly be seen. In Trace (C),... 

Place the bagged sample snugly in the sample port of the reflectance sphere, with the freshly sliced surface facing inward (toward the detector). Record reflectance (% of standard) from 420 to 700 nm. 

Records are kept of when a sample was collected, the method of collection, who collected the sample, what the elapsed time was between harvest and freezing, the conditions under which it was stored, how it was shipped to the laboratory, and when it was shipped. When a sample arrives at the laboratory, the condition of the sample is checked and recorded. Then the information on the sample bag (sample number, application rate, preharvest interval, etc.) is compared to the trial information sheets which are submitted along with the samples. Any omissions or discrepancies are corrected at that time. If there is an omission or discrepancy that cannot be easily corrected by a telephone call from the sample processing laboratory to the field scientist, the study director is notified. The study director must make the decision about the validity of the sample and put a note in the data file explaining how the problem was corrected or that the problem could not be corrected and the trial is to be abandoned. If the trial is dropped, Quality Assurance is notified, the trial is deleted from the active Master Schedule, and an explanation is put in the study file. 

Bands of interest are excised with a razor blade. At this stage the samples are quite stable. They should be kept moist, but not submerged, and should be stored in Eppendorf tubes or sealed in plastic bags. We have successfully shipped bagged samples at ambient temperature in overnight mail, but shipping on dry ice is usually recommended. 

In this study the filter samples were halved, bagged in cleaned polyethylene tubing, and first analyzed by PGAA using an external irradiation facility constructed by our group at the National Bureau of Standards (NBS) research reactor (9). PGAA provided determinations of the elements B, S, and Cl on the treated filters, and B, S, Cl, Si, Cd and often others on the particle filters. For analysis of short-lived isotopes by INAA, the bagged samples were... 

Figure 2. Variations of cross contamination of tritium from concrete (--9 kBq/g) with the passage of time (Expt. 1). RO water in open and closed scintillation vials were stored in airtight Kilner Jars with a bagged sample of active concrete at room temperature, in a fridge and in a freezer for 1 day, 5 days, 10 days, 15 days, 20 days and 30 days.

The glove juice method is considered to be an aggressive sampling technique however, results of experiments described above suggest that it does not recover 100% of bacteria placed on the skin. We conducted a smdy to specifically determine the extraction efficiency of the glove juice/plastic bag sampling procedure... 

Eight subjects were enrolled into the study. The nail beds on one hand of each subject were sealed with acrylic nail polish, while those of the other hand were kept open. For the base count, the subjects hands were inoculated with E. coli. Immediately following the contamination step, the organisms on the subjects hands were sampled using a plastic bag sampling procedure. The subjects hands were sampled two more times using this procedure to determine the efficiency of recovery of bacteria. 

For the test procedure, subjects hands were contaminated with the test organisms. Subjects treated their hands once with a liquid soap product. They washed their hands for 30 seconds and rinsed for 15 seconds. Afterward, hands were sampled three times using the plastic bag sampling procedure. Aliquots of the three sampling solutions were diluted, plated, and incubated. Following incubation, the number of CFUs was enumerated. Antibacterial activity was determined by comparing the number of bacteria removed from the hands after washing once with the test product to the number of bacteria removed from unwashed hands. 

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