Air Sensitive Sample Analysis
Many samples currently being tested for purity are those that readily oxidize when exposed to air. Most of these samples are also extremely sensitive to environmental moisture. For an accurate evaluation of purity, air-sensitive samples require weighing under an inert atmosphere. Midwest Microlab maintains an oxygen and moisture free handling system. Very highly hygroscopic samples many times will also benefit from this type of special handling. The glove box system used is normally operated with either a nitrogen or helium atmosphere. The equipment has a drying train that is in motion during use and works to collect any residual moisture present in the immediate atmosphere. Purging is done under vacuum before any samples are handled. An oxygen monitor continually checks the internal environment for the presence of oxygen. Samples are weighed and sealed in the inert atmosphere and subsequently transferred out for analysis through a similarly vacuumed chamber.
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.
Midwest Microlab can determine the following elements on air-sensitive samples: Carbon, Hydrogen, Nitrogen, Chlorine, Iodine, Fluorine and Phosphorus.
Due to the methods used, we cannot analyze for sulfur, bromine, or oxygen on air-sensitive samples.
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 even under advantageous conditions. The sealed capsule is moved directly to combustion upon removal from the glove box. Every effort is made to secure the best possible measurement of elements requested. Very air sensitive samples are best sent sealed in small break-open ampoules (see picture above). 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 to the analyst 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
Always be sure to note any know toxicities or hazards. Midwest Microlab does not handle any samples containing Osmium.
