Description_x000D_ General description_x000D_ This proficiency testing sample is produced in accordance with ISO/IEC 17043:2010. All information regarding the use of this material can be found in the reporting packet supplied for each sample._x000D_ Preparation Note_x000D_ Sample Preparation_x000D_ To prepare the solution partially fill a 1000mL volumetric flask with reagent-grade water (near 20ºC) and add 1mL of trace-metal grade nitric acid._x000D_ Open ampoule PE1209-20ML (be careful to avoid cuts on glass) and transfer 10.0mL of concentrate to the volumetric flask._x000D_ Fill the flask to volume with reagent-grade water and mix well._x000D_ The sample is now ready for immediate analysis._x000D_ A reagent-grade blank should be analyzed concurrently for background correction. The water blank should be made to match the acid matrix of the standards and samples._x000D_ NOTE: The 0.15% v/v nitric acid specification is a minimum; the amount and type of acid may be altered in order to match the acid matrix of standards or analytical procedures if needed.._x000D_ Other Notes_x000D_ Proficiency testing samples are presented as single blind. No values for the samples are released until the testing period concludes. Values of analytes vary lot to lot._x000D_ Proficiency Testing Schedule (2019-2020)_x000D_ Wastewater_x000D_ WP19-1 January 16 - March 1, 2019_x000D_ WP19-2 March 27 - May 10, 2019_x000D_ WP19-3A May 15 - June 28, 2019_x000D_ WP19-3B July 10 - August 23, 2019_x000D_ WP19-4 September 25 - November 8, 2019_x000D_ WP19-5 November 20 - January 3, 2020_x000D_ WP20-1 January 15 - February 28, 2020_x000D_ WP20-2 March 25 - May 8, 2020_x000D_ WP20-3A May 13 - June 26, 2020_x000D_ WP20-3B July 8 - August 21, 2020_x000D_ WP20-4 September 23 - November 6, 2020_x000D_ WP20-5 November 25 - January 8, 2021_x000D_ Quick-Turn Study - (non-scheduled proficiency test that is available at any time)