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How long should samples be kept before analysing Total Organic Carbon?
Wiki User
∙ 12y ago
As with any analytical test method - sample storage and storage conditions should be evaluated for stability. In particular to TOC samples, the FDA explicitly states on their website that "If TOC samples are being held for long periods of time before analysis, a firm should verify the impact of sample holding time on accuracy and limit of quantitation."
One can achieve this type of study by creating a sample stability test plan over a lengthy period of time to determine the variability in stability. A 12 week study is sufficient, where you are testing vials of a TOC standard at a specific concentration from time zero to time end. All vials should contain the same concentration, be stored in the same vial and the same temperature during the study. You would test the accuracy of this standard each week and determine at what point the sample stability is in question. Any result lower than 85% should be questioned.
Wiki User
∙ 12y ago
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Is carbon black organic or inorganic?
No. the word organic means "to contain carbon" but carbon, carbon monoxide and carbon dioxide were discovered and understood well before the concept of "organic" came about. So we historically did not label them as organic and still do not. Also, that which we use the word "organic" for is usually long chains of organic molecules and CO2 and CO are small molecules. So they dont direclty apply.
What organic molecule is most closely related to nucleic acids?
Since proteins are organic molecules (carbon-containing and essential to life), the closest organic molecule to proteins is proteins. Before one can determine which organic molecules are most closely related to proteins, one would first have to define what particular aspects of relatedness one is interested in, ie. solubility, chemical composition, structure, function, etc.
What does the complete combustion of coal produce?
The complete combustion of organic compounds produces Carbon Dioxide (CO2), Water (H2O), and a residue of any impurities which were present in the coal before combustion. Complete combustion requires a great surplus of molecular Oxygen to occur.
What was coal before it was coal?
it is an organic matter of plants which were decay and decompose after their termination
Why is it important to remove the CO2 from the solutions before doing the titration?
It is important to remove the carbon dioxide from the solutionf before doing the titration because, carbon dioxide mixed with water is acidic, it produces an acid.
Is carbon black organic or inorganic?
No. the word organic means "to contain carbon" but carbon, carbon monoxide and carbon dioxide were discovered and understood well before the concept of "organic" came about. So we historically did not label them as organic and still do not. Also, that which we use the word "organic" for is usually long chains of organic molecules and CO2 and CO are small molecules. So they dont direclty apply.
Who discovered graphite?
Sometime before 1565(some say as early as 1500)
Why do proteins considered organic molecules?
They are made from many carbon atoms.
What makes an organic energy or candy bar purely organic?
organic foods have no relation to the science of organic chemistry. organic foods have to be grown with certain guidlines to be labelled an organic produce though even this can vary from place to placebut speaking in a broader sense, organic substances are any molecule that has a carbon backbone this include a wide variety of substances ranging from gasoline to aspirin to the proteins and lipids that make we humansAnswerThe same thing that makes anything organic. Carbon. Every product that contains carbon is, by definition, organic. People like the previous respondent have tried to steal the word and change it's meaning. But look it up in any dictionary (hurry, before the hippies get them all changed), and you will find that what I say is true. Now, "purely organic" is another story. In order to be purely organic, a product can contain only carbon. The only products that qualify are graphite and diamonds. There's no such thing as "purely organic food", unless, of course, you like eating graphite and diamonds.
Do organic compounds have a higher boiling point?
Higher than what? Some organic compounds (e.g. propane, butane) have very very low boiling points making them gases at room temperature. Certain inorganic compounds (e.g. tungsten carbide) have boiling points so high that before those compounds boiled all organic compounds would not only have boiled but would have decomposed into their elements or very simple inorganic carbon compounds (e.g. carbon monoxide, carbon dioxide).
How do you get free food samples?
You can contact the manufacturer and ask if they have samples. I've done this before. There are also several web sites that catalog various free samples, for which you can apply.
How do farmers test the pH level in soil?
before begining to farm one should send several soil samples for lab testing. they are testing for soil composition, pH, nutrient levels, organic matter and water permiability
Where can you find good free pad and tampon samples?
Most companies no longer give free samples of tampons or pads.The only company I know who still does this is Cottons organic tampons and pads, they will send small sample packs containing a tampon, pad, and liner. You can buy softcup samples from their web site which isn't free but is a cheap way to try softcups before buying a full pack. Otherwise you may sometimes see free samples advertised on freebie sites but it's really uncommon these days.
Before George Gallup polling samples were often?
biased.
Why is it necessary to grind the food samples before testing?
ur face
Before George Gallup which characteristic did polling samples often have?
biased
When do you not take a blood sample?
Samples must be take before milking
