Humor is a Dish Best Served Cold
Feb. 21st, 2007 05:22 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
ladynox25
As I may have said once or twice before, I work at an environmental analytical laboratory. Which means that our job, day in and day out, is to test the various kinds of samples we get for various kinds of things. In order to achieve the best, most reliable, most accurate results possible, most, if not all of the samples we get have to be preserved. The point of preservation is, of course, to retard growth, decay, degradation, or other change that might affect the sample's characteristics. Sample preservation comes in two forms, chemical and thermal.
Chemical preservation includes such things as acidification (for which we use either H2SO4 or HNO3, depending on the test), basification (NaOH), and other miscellaneous chemicals such as hexane and sodium thiosulfate (which is used to preserve bacteriological samples).
Thermal preservation is simple; every sample, whether chemically preserved or not, is supposed to be shipped to us on ice. In practice, of course, this doesn't always happen, especially when someone comes in the door with a sample in their hand, but in most cases, when a sample is shipped, it is shipped on ice. This lowers the temperature of the sample to approximately 4 C.[1] For some types of samples, such as BOD samples, this is the only preservation they get.
I heard today at work that one of our clients, apparently inspired by the "If a little is good, more must be better!" school of thought decided that if putting samples on ice at 4 C was good preservation, putting them on dry ice would do the job even better.
Think about that for a second.
When the sample cooler was opened in Login, the glass containers had shattered from the cold and the plastic containers were frozen solid. By the time they had warmed up enough to thaw, the samples were out of holding time for their tests. So now, the client has to resample everything.
[1] I should add here that once a sample gets to us, it is also stored at 4 C, either in the huge walk-in cooler or in a dedicated refrigerator.
Chemical preservation includes such things as acidification (for which we use either H2SO4 or HNO3, depending on the test), basification (NaOH), and other miscellaneous chemicals such as hexane and sodium thiosulfate (which is used to preserve bacteriological samples).
Thermal preservation is simple; every sample, whether chemically preserved or not, is supposed to be shipped to us on ice. In practice, of course, this doesn't always happen, especially when someone comes in the door with a sample in their hand, but in most cases, when a sample is shipped, it is shipped on ice. This lowers the temperature of the sample to approximately 4 C.[1] For some types of samples, such as BOD samples, this is the only preservation they get.
I heard today at work that one of our clients, apparently inspired by the "If a little is good, more must be better!" school of thought decided that if putting samples on ice at 4 C was good preservation, putting them on dry ice would do the job even better.
Think about that for a second.
When the sample cooler was opened in Login, the glass containers had shattered from the cold and the plastic containers were frozen solid. By the time they had warmed up enough to thaw, the samples were out of holding time for their tests. So now, the client has to resample everything.
[1] I should add here that once a sample gets to us, it is also stored at 4 C, either in the huge walk-in cooler or in a dedicated refrigerator.
