Sample Submittal Form and Instructions
for XRF or ICP-MS Analyses
School of the Environment
1228 Webster Phys Sci
Washington State University
Pullman WA 99164-2812
Submitted samples should be accompanied by detailed payment information. We can accept a purchase order, check, bank transfer or credit card. Please do not mail card information with your samples. You can contact us by phone with card number, expiration, and security code when billing is initiated. Please include the name, address, phone, and email for your billing contact person. Billing will be initiated upon completion of services unless otherwise requested.
You can view our price list here.
Sample Submittal Form
Please email a copy of the submittal form to email@example.com, and print a copy to include with your samples. Please provide rock type and location information (required for the research rate), and note any unusually high or low concentrations expected, unusual mineralogy or sulfides, carbonates, or clays in the “Comments:” section on the submittal form.
Don’t hesitate to email or call if you have any questions prior to submitting your samples.
NOTE: Please let us know the type of grinding container used if you are submitting powders not prepared here.
NOTE: For SOIL samples from international addresses, please contact us prior to shipping for soil import permit forms.
Whole Rock Samples
Samples can be submitted as hand samples, picked chips, or ground powders for no difference in price. We prefer to powder samples because the powder must be very fine to ensure good replication of XRF and ICP-MS data. We also have very efficient equipment for chipping, splitting, and powdering. Since grain size is an important factor for fusion procedures, we will regrind powders coarser than 50 microns (samples that feel gritty when rubbed across a piece of paper).
Soils, Organic rich, or Otherwise Unusual Samples
We have had success analyzing non-“rock” samples, but sample preparation and analysis times can be substantially longer due to the difficulty of getting a properly homogeneous bead out of the oven. Please contact us prior to shipping your samples if you suspect they will fall into this category.
We normally grind 20-120 gram samples in tungsten carbide (WC) ring mills. These containers do not contaminate with elements of concern for most isotopic analyses except Hf (W interference). They do contaminate with W, Co, and minor Ni. Nb and Ta contamination for pure silica glass ground in our Rocklabs WC is at or below ICP-MS detection levels.
For customers wanting the return of their powders to use for Hf isotope analyses, or with samples that are likely to be extremely depleted in Nb and Ta, we also can grind in an agate ball mill if requested. Agate grinding will add 1-2 weeks to turn around time for the additional processing. The agate mill will also contaminate with silica and reduce the analytical precision for SiO2.
Normal Sample Size
The ideal sample is 20-50 grams of chips or hand sample that is free of weathering, moss, dirt, etc. Hand samples should be of sufficient size to assure homogeneity (see “Coarse Grained Samples” below). Our minimum sample sizes are given below, but, it is best to avoid minimum weights because we cannot rerun samples which do not pass quality control standards on the first attempt.
Minimum Sample Size
|XRF + ICP-MS||3.5 grams*|
|ICP-MS only||0.5 grams*|
* LOI measurements, which are a valuable quality control check and strongly recommended, require an additional 0.5 grams of sample.
**ICP-MS straight dissolution should only be considered for glasses, mineral separates, cherts, etc, and not whole rock samples, as refractory phases WILL NOT be consumed in the dissolution process.
Coarse Grained Samples
For coarse grained samples, larger amounts (> 100 grams) are needed to avoid sampling bias. Sub-sampling of coarse plutonic, metamorphic, and even volcanic rocks using commonly employed methods (coning and quartering and riffle splitting) can introduce bias and degrade precision, therefore we coarse chip, fine chip (<2mm), and sub-sample using a rocklabs rotary splitter. As long as you submit sufficient quantities of sample, sub-sampling error is reduced to the level of analytical error with this procedure.
Very Small Samples
We can grind samples less than 3 grams in either WC or agate ball mills with loss of only 10-20 mg per grind, but turn around time will be extended by 50%-100% to perform these small bead analyses due to increased preparation and analysis time.
For 15 mm (half size) XRF pellets optimal weight 1.1 gm; min. wt. 0.5 gm
For 8 mm (quarter size) XRF pellets opt. wt. 400 mg; min. wt. 150 mg