Elemental Analysis Sample Submission
Sample Submission Form
Please use this Sample Submission form, in Excel format. Using this enables us to more efficiently acquire and process your data. Up to fifteen samples can be submitted on each form. Download the form to your computer and fill it out electronically. Sample ID's should be 4-8 alphanumeric characters. You MUST e-mail the completed Excel version of the form before or when you submit your samples.
Submit completed sample submission forms to Sarah Cady and cc: Avery Carlson.
Instructions for Submitting Stable Samples
The schedule may vary depending upon the work hours of the undergraduate assistant who weighs the samples. If you are on a tight timeline, please talk to us before sample submission. Your results will be emailed to you in excel format. Remember to retreive your unused samples, otherwise they will be disposed. If you do not wish to retrieve your unused samples, please provide disposal instructions.
- If less than five samples are submitted for CHNS, the weekly run may be canceled. Please contact us if you need analysis on a tight timeline.
- Approximately 2-3 milligrams of sample will be combusted in each run, and samples are typically run in duplicate or triplicate. Therefore, samples should be submitted in quantities of 8-12 mg in order to ensure that sample transfer can be accomplished easily. The physical nature of your sample and the vial will determine this. You may retrieve your excess sample when the analysis is finished.
- Samples must be completely pure and completely dry. It is preferable for you to powder your sample rather than submit large chunks. Please consider ball milling, cryo grinding, or other pulverization techniques. (Such equipment is available in MSE.) We have a small mortar and pestle for samples that are easily ground.
- Oils, pastes, and liquids can be accommodated with some difficulty. Submit considerable excess.
- Please list any special combustion conditions for your compounds referenced in the literature or in technical notes. Un-referenced comments will be ignored. The default combustion conditions should work for greater than 90% of all samples.
- Two runs are required to verify the precision of the measurement.
- The CHNS combustion tube is used by default. However, an accurate Sulfur % requires the addition of vanadium pentoxide. We generally run samples with vanadium pentoxide unless otherwise specified.
- CHNS runs take 720 seconds for each sample.
- It is not necessary to tell us the formula of your sample if you do not know it.
Please feel free to discuss your project with us at any time.
Instructions for Submitting Air Sensitive Samples
The best way to submit air-sensitive samples is for you to pre-weigh the tins using our scale, transfer them into the glove box, and weigh in the glove box if possible. If not possible, you can re-weigh just prior to analysis. This is tricky if vanadium pentoxide is used, however.
Procedure for weighing air-sensitive samples in a glove box
Please notify us several days in advance if you plan to submit air-sensitive samples. The capsule press has the tendency to live in a few glove boxes for extended periods, and we may need to track it down. You will pre-weigh several tin capsules using our scale, and place in individual vials labeled with a number. Inside your glove box, you will load approximately 2 mg of sample into each tin vessel, then crimp using the capsule press. It is important that you have a balance inside your glove box in order to roughly weigh the amount you are putting into each tin capsule. Weights may range from 1.5 mg to 2.5 mg.
Place each crimped tin vessel into a numbered small vial. Cap the vial. It is important not to mix up the vials as inputting the correct mass into the table is vital to ensure accurate results. If the sample is extremely air sensitive, you may place the numbered vial inside a larger vial, or seal the vial with electrical tape or parafilm.
When you submit your samples, clearly identify them as Air Sensitive. As long the small vials and the larger vials are filled with inert gas (typically nitrogen, helium or argon) the samples should be stable, however you MUST notify us that you would like to submit air sensitive samples so that we can coordinate our analysis schedule with your sample submission, and the vials can be outside of the glove box for as little time as possible.
The sealed tin vessel will be exposed to air for about sixty seconds during the final weighing process. As long as the tin vessel has been properly crimped and sealed (without any cracks or tears in the tin) we will have an excellent chance of getting good results for you.
You will need to practice loading samples into the small tin vessels. Using any powdered sample, practice loading, sealing, and crimping the tin vessels on your lab bench. Obviously you do not need pre-weighed vessels for practicing your technique. Next, practice your technique working inside your glove box. Only when you can consistently load, seal and crimp tin vessels while working inside your glove box should you begin loading your air sensitive samples into pre-weighed vials for analysis.
A number of small tools including tweezers and spatulas are necessary. You may borrow ours if you ask for permission.