Non-preserved snowmelt (filtered to 0.1 um) Precipitation (low ionic-strength) sample (500 mL): typically Major ion sample (500 mL): chlorinated with sodium hypochlorite (filtered to 0.2 um) Trace element sample (500 mL): chlorinated with sodium hypochloriteĪnd acidified with HNO3 (pH<2 filtered to 0.2 um) View the list of available SRSs from our inventory.Īll samples are in the dissolved phase. Order previously prepared SRSs, please email the SRS Project Chief. To order samples for the current inter-laboratory comparison, please visit our order page. If you can not fully access the information on this website, please Jim Simmons, Branch Chief, Quality Systems Branch (303) 236-1835 Note: All samples are in the dissolved phase (filtered to 0.1 to 0.2 um) so bottle aliquots are homogeneous.Ĭreating an unfiltered SRS cannot be prepared without very high variability.
No cost for samples (some restrictions) except for shipping.Samples prepared with natural-matrix water (more similar to real world environmental samples).Laboratories may order previously made SRSs by contacting the SRS Project Chief. Labs based on the deviation (z-value) from the median and percent difference. Laboratories can compare their results to other State, municipal, and university laboratories can participate even though theyĭo not provide data to the USGS.
This project is typically no open to international laboratories. Ascertain the bias and variability of analytical methodsĪpproximately one hundred and twenty-five USGS and non-USGS laboratoriesĪre actively participating (from 40 states) in the project and six standard reference sample types areĪvailable (Trace Element, Major Ion, Precipitation, Mercury, Low-level Nutrient,Īnd Regular-level Nutrient).Reference materials to meet these needs and Identify quality assurance needs with respect to environmental analyses and develop new.Provide a library of carefully prepared, homogeneous, stable reference materials.Evaluate and improve the performance of participating laboratories.Since that time, objectives of the project have been to accomplish the following: Twenty-three USGS laboratories participated in the determinations of six analytes. The project began in 1962 with a single sample containing major constituents that was prepared from distilled water and reagent grade chemicals.
Active Labs (participating within last 2 years)ĮLEMENTS * MAJOR IONS * PRECIPITATION * MERCURY
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