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FAQ

faq

How much sample is required for my analysis?


Each CHN analysis should include at least 5mg of transferable sample. Halogens depend upon the theoretical percentages expected.

% expected %Cl %Br %F %O %P %I %S
1-5% 25mg 10mg 20mg 20mg 4mg 5mg 30mg
5-10% 10mg 5mg 10mg 10mg 3mg 4mg 15mg
10-20% 5mg 3mg 10mg 5mg 3mg 3mg 8mg
above 25% 4mg 2mg 10mg 4mg 2mg 3mg 8mg

*All sample sizes are meant as transferable from the vial.

**If the sample’s consistency is sticky or static sensitive, additional sample is required.
 

Is it important to list theoretical percentages?


Its important that submitters list a molecular formula. This allows us to rule out interferences as well as select the optimal sample size for highest accuracy. If mistakes are made due to lack of input on this matter, there is an additional charge for rechecking results.

 

Can you provide RUSH service for my sample?


Yes, we do and at NO ADDITIONAL CHARGE. We ask that submitters limit RUSH requests to only a few samples requiring the highest priority. Rush analyses must also be limited to CH, N, CI, S, and Br analyses with same day turnaround. Please note that samples with fluorine, oxygen and phosphorus normally cannot be completed the same day.

 

Do you handle air-sensitive samples?


We maintain a Nitrogen glove box at 40ppm of Oxygen. There is an additional charge of $25.00 per sample. It is important that samples are sealed adequately when shipped. Air sensitive samples must be transferrable which excludes heavy thick oils that cannot be transferred adequately for this type of analysis. Due to techniques used, we cannot analyze sulfur on an air sensitive substance. Drying is never able to be done on air sensitive samples. We ask that samples with extremely strong stench should be annotated as such.

 

Are there any specific types of samples that you do not handle?


Yes, due to the health and safety of personnel, we do NOT handle any compounds containing Osmium, Non-Depleted Uranium, or Thallium or with a high toxicity or strong stench. We do not handle any Finished Pharmaceuticals for release or Highly volatile liquid samples with boiling points of less than 40 deg C.

 

How did you perform the analyses?


CHN analysis is performed via combustion at 990 deg C with the elemental analyzer.
Sulfur, Chlorine, Bromine, and Iodine are done via flask combustion and subsequent titration.

Oxygen is preformed by pyrolysis at 1200 deg C and determined gravimetrically. (Unterzaucher Method). Oxygen determination is done on purely organic substances only (no metals or phosphorus present).

Fluorine is done by bomb digestion and subsequent determination by ISE.

 

Do you perform organic trace analysis?


No we don’t. Phone us if you have a need for this. We can recommend a qualified laboratory for this service.

 

Do you offer discounts on your current fees?


Yes we do offer discounts based upon monthly sample volume. Phone us for details.

 

What Organizations do you belong and what Licenses do you currently maintain?


Midwest Microlab is licensed with the USDEA to handle all controlled substances Class I thru V.