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_ This PT sample is packaged as a 1.5 mL concentrate._x000D_ The PT sample is not preserved._x000D_ The sample must be stored at 4 °C._x000D_ Sample Preparation_x000D_ Allow the ampule concentrate to equilibrate to room temperature. Analyte concentration range 0.3 to 10 μg/L._x000D_ To prepare solution, add 1 liter of reagent water to a 2 L separatory funnel._x000D_ Open ampule PEO-259 (be careful to avoid cuts on glass) and transfer exactly 1.0 mL of the concentrate to the separatory funnel._x000D_ Mix well._x000D_ This represents the sample for analysis._x000D_ For calculations, assume initial sample volume was 1000 mL._x000D_ Other Notes_x000D_ Proficiency testing samples are presented as single blind. No values for the samples are released unti the testing period concludes. Values of analytes vary lot to lot._x000D_ ._x000D_ Proficiency Testing Schedule (2020-2021)_x000D_ Wastewater_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_ WP21-1 January 13 - February 26, 2021_x000D_ WP21-2 March 24 - May 7, 2021_x000D_ WP21-3 July 7 - August 20, 2021_x000D_ WP21-4 September 22 - November 5, 2021_x000D_ Quick-Turn Study - (non-scheduled proficiency test that is available at any time)