We make our world significant by the courage of our questions by the depth of our answers. Chemistry Why would anyone need parts Ppm ppb ppt simulation dating billion ppb accuracy over parts per million ppm in gas chromatography, or anything else. Why would anyone need parts per billion ppb accuracy over parts per million ppm in gas chromatography, or anything else.
As the title suggests, I'm wondering why more accuracy at that level is better, specifically Ppm ppb ppt simulation dating regards to gas chromatographers gc. Are there things that a ppb gc can do better than ppm gc? The concentrations of some important Ppm ppb ppt simulation dating in the atmosphere are in the range methane at roughly ppb until modern times when it has gone up to
Ppm ppb ppt simulation dating ppb range.
Scientists were very excited when several measurements claimed to detect methane at all on Mars. A Mars rover team recently published results that any methane in the Martian atmosphere is at concentrations below 11 ppb. Important ozone destroying compounds exist in the Earth's atmosphere at levels in the ppt parts per trillion range, see first link above. A comparison to famous poisons can be enlightening. Ricin is lethal in concentrations around 22 micrograms per Ppm ppb ppt simulation dating of body weight.
This is equivalent to 22 ppb. Scientists use ratios of elemental isotopes to find out all sorts of interesting things: In general, the more accuracy and precision a measurement is capable of, the more information can be gleaned from it.
Ppm ppb ppt simulation dating concentration changes and comparing to the current temperatures at those times for example.
Remember, just because something is very small doesn't mean that it isn't important.
If all of this doesn't start to convince you, maybe Frank from MiB will. Some substances are so potent in their effects, or so or build up Ppm ppb ppt simulation dating time from small concentrations, that detecting them in extremely minute quantities Ppm ppb ppt simulation dating necessary.
Check out LSD, for example. Put one dose in a one-liter bottle of water and you have a concentration of parts per billion, or so. another example, Botulinum toxin is the most toxic substance known, with a median lethal dose in humans being 2 nanograms per kilogram of bodyweight.
That's 2 parts per billion. One ounce of the stuff could kill every person in any major city, 25 million deaths. A kilogram is 10 grams.
So, 2 ng per kg is actually 2x10 or 2 parts per trillion, not billion. Some Persistant Organic Pollutants POPs have
Ppm ppb ppt simulation dating effect with very low dosages, and they also tend to bioaccumulate, so ingesting very small amounts over and over can lead to high concentrations in the body. This is what
Ppm ppb ppt simulation dating use. You can see the Ppm ppb ppt simulation dating oven on the left side and the MS is what it's sitting on.
The big hump in the middle is a large magnet. So a picogram is 10 grams, therefore we're measuring lower than a part per trillion pptotherwise stated as hundreds of parts per quadrillion ppq.
Reminds me of the days when I was taught particle cross sections in units of barns.
Aside from sometimes often needing to measure very small amounts, better sensitivity is great from a technical point too. If I'm measuring in the 10 ppm range and my instrument is only sensitive to 1 ppm or has a baseline noise of 1 ppm then my signal Ppm ppb ppt simulation dating noise will be
Ppm ppb ppt simulation dating worse and I will need more replicates to be confident in my data.
Furthermore, if I don't get a signal, I can only conclude that I have less than 1ppm in my sample. The measure of
Ppm ppb ppt simulation dating signatures for various stable and non-stable isotopes routinely needs ppb accuracy to extract any meaningfull value.
This stuff is exactly what I do in my lab.
The work I'm doing right now only goes down to ppm, which is good enough for the EPA. For other molecules, we need to get down the the ppb level in order to comply with EPA regulations.
The reason being is that the EPA, and other governing bodies, have determined that a given pollutant can be harmful at such low levels. So I guess I'm
Ppm ppb ppt simulation dating that it really depends on what you're looking for, and for what application. Again for the PCBs, the regulatory Ppm ppb ppt simulation dating for one matrix is 50 ppm, so if I got a sample and determined the concentration to be less than 50ppm, I wouldn't care if it was 1ppm or 1ppb, either way its good.
Now if I were analyzing the sample for Arsenic, I would need to come up with a new set of experimental parameters to get down to the ppb limit, because that is the regulatory limit for Arsenic.
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Want to add to the discussion? I should think less. In the case of Pb Isotopes, that accuracy level translates in at least Ppm ppb ppt simulation dating awesome capabilities: Earth and Planetary Sciences.
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