Analytical Services: Sample Requirements
 

Carbonates:

Carbonate samples should be ground (<0.3mm particle size) and dried to facilitate the best reaction and determination of stable isotope ratio. Send in small clean vials or centrifuge tubes with snap top

Carbonate samples will be preroasted in vacuum to remove possible organic contamination unless we are notified otherwise. Other prepatory chemistry should be completed prior to shipment of samples. Alternatively, arrangement can be made for chemical pretreatment at the cost listed on the Fee Schedule.

Note: Please indicate mineralogy of samples (e.g. calcite, aragonite, dolomite etc.)

Water:

Water samples should be sent in clean glass or plastic bottles. Each sample should be individually wrapped with bubble wrap or other material to prevent breakage. Prefiltering the samples is not necessary and head space in the bottles is not a problem. However, evaporation will affect the isotope ratio of the water. Bottles with a poly-seal top or other like seal are best. In addition, the sample bottle caps should be wrapped with parafilm.

For oxygen isotope (δ18O) analysis, we routinely analyze waters with seawater salt concentrations or lower. We do not analyze hypersaline waters.

For hydrogen isotope analysis, the waters should be free of sulfides, organic acids, and mercury. If the sample received needs chemical treatment before analysis, we can do this at the cost listed on the Fee Schedule. Please indicate whether pretreatment is required.

DIC:

Samples submitted for vacuum line extraction of dissolved inorganic carbon (DIC) and δ13C analysis should be stored in 10-11 ml clean glass screw top vials. Samples should have no head space and the water should be poisoned with HgCl2 or some other agent to prevent bacterial growth. Cover the meniscus of the sample with a small piece of parafilm, cap tightly and wrap the cap with a strip of parafilm.

Samples whould be prefiltered if suspended carbonate is in the sample.

Bottles should be individually wrapped with bubble wrap to prevent breakage.

Tube CO2:

Purified CO2 can be stored in clean straight 6mm OD pyrex tubing. End seals must be straight over the diameter of the tube. Overall length should be 4"-6". Pressure in the tube should not exceed 1-2 atm STP.

 

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