Air Sensitive Sample Analysis
For an accurate evaluation of purity, air-sensitive samples require weighing under an inert atmosphere. Midwest Microlab maintains a reduced oxygen and moisture free handling system. Very highly hygroscopic samples many times will also benefit from this type of special handling. The glove box is operated with 99.9% EXTRA dry nitrogen. Purging is done under vacuum before any samples are handled. An oxygen monitor continually checks the internal environment for the presence of oxygen. NOTE: this monitor rarely shows a zero count. Though we continually strive for the best results, no inert chamber can be absolutely 100% free of oxygen and/or moisture. Samples are therefore weighed as quickly as possible under these conditions. Every effort is made to secure the best possible measurement of elements requested. Experience has shown that samples that are able to withstand 15 sec exposure at 50 ppm oxygen work very well. Samples much more sensitive than this usually won’t work out well.
The system also contains electrostatic reduction equipment to aid in handling. Samples weighed under inert atmosphere MUST be transferrable. These samples must clearly be either liquids or solids. Very thick, sticky substances cannot be transferred or handled under this system.
Air sensitive handling is very time consuming work. The air sensitive handling at Midwest Microlab is therefore limited to the following elements ONLY: Carbon, Hydrogen, Nitrogen and, Fluorine. Sample submission form MUST be filled out completely and included with these samples.
We do NOT handle air-sensitive samples containing any of the following:
Osmium, Uranium, or Thallium
Small break-open ampoules (see picture above) are the best way to send these type samples. This helps to eliminate any degradation in transit, which may skew results. Samples that are only slightly oxygen sensitive, can give good results when sealed tightly in screw cap vials. For these a second sealed outer vial should be included.
Samples handled under inert incur an additional $25.00 charge per sample. PLEASE ALWAYS make sure to clarify that you desire this service. Be sure to note on the submission form “handle under inert” or “air-sensitive sample”.
As with all analysis, samples MUST be highly purified to achieve good results. It is always best if submitters e-mail us prior to sending air-sensitive samples.