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Sample Submittal Instruction

For XRF or ICP-MS Analyses
All analytical work should be accompanied by a payment method (purchase order, check, or credit card information), sample list, rock type and location information (see the submittal form), unusually high or low concentrations expected, unusual mineralogy or sulfides, carbonates, clays and type of grinding container used if submitting powders.

Our prices do not include loss on ignition determination (LOI), this can be done by special request for an extra fee of $5/ea.

Samples can be submitted as hand samples, picked chips or ground powders for no difference in price. 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).

We can grind in either agate, tungsten carbide, hardened steel or Diamonite (sintered sapphire, for small samples only). These containers will not contaminate with elements of concern for most isotope analyses except Re/Os (steel). Contamination we know of so far is: W, Co, and Ni in tungsten carbide, Fe, Ni, Cr, Cu, Re, Os in steel, SiO2 (<0.1%) in Agate.

For samples that require concerns about homogeneity, the optimum sample submitted would consist of 30-50 g of small (<1 cm) picked chips. We will then grind all if using tungsten carbide or steel, or minichip (<2mm) the entire sample and split down to 15 g for grinding in agate.

Excess sample will be returned for no extra charge.

• XRF: 30 g picked chips, or 3.5 g fine powder*. Minimum to grind without contamination problems is 10 g, Minimum to weigh is 2.5 g, and only if powder is fine enough (see above).

• XRF & ICP-MS: 15 g picked chips, or 3.5 g agate ground powder* (<50 microns). Minimum to grind without contamination problems is 10 g, Minimum to weigh is 3.5 g, and only if powder is fine enough (see above).

• ICP-MS fused bead procedure (for most rocks): 30 g picked chips, or 2.0 g powder (need not be as fine as for XRF). Minimum to weigh is 1.0 g.

• ICP-MS straight dissolution procedure (for glasses, mineral separates, oceanic basalts, cherts): 200 mg powder or glass chips. Minimum to weigh is 100 mg.

*It's not advisable to send minimum size samples unless absolutely necessary, because the likelihood of contamination or sample loss is increased with small samples.

Samples under the minimum weight might still be successfully prepared, but could be used up without obtaining a useable bead.

We can use small masks to measure 15 mm XRF beads made from 1.1 g or 8 mm beads from 0.4 g, precision is degraded by a factor of about 2 to 3 for each step down in size. Please consult with us if you need to submit such small samples, they may need special handling and extra costs may be involved.

If you have any questions, feel free to contact Diane Johnson Cornelius (XRF) and Charles Knaack (ICP-MS)