caa a22 4500 605465967 CHVBK 20210128100305.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s00769-015-1122-7 doi (NATIONALLICENCE)springer-10.1007/s00769-015-1122-7 Coordination of organochlorine pesticides in water proficiency testing schemes in South Africa [Elektronische Daten] [Désirée Prevoo-Franzsen, Nontete Nhlapo, Laura Quinn, Maria Fernandes-Whaley] The National Metrology Institute of South Africa (NMISA) developed a proficiency testing (PT) scheme for the analysis of organochlorine pesticides (OCPs) in drinking water, for a limited number of participants. Two identical 1L water samples fortified with OCPs at the ng/L concentration level were distributed to each participant. The concentration range of pesticides was selected to mimic regulated trace levels in drinking water. The assigned value was based on the traceable, gravimetrically prepared value of each of the analytes spiked into the water samples. The samples were adequately homogeneous and stable over the 3-week reporting period. The standard deviation for proficiency assessment was determined using the alternate Horwitz model, and participant performance was reported using z-scores. E n numbers were also included in the PT reports to motivate laboratories to evaluate the suitability of their measurement uncertainty estimations. One of the biggest challenges associated with coordinating this PT scheme remains courier costs and delays in sample distribution within Africa, whilst the accurate determination of pesticides at trace concentration levels remains the biggest challenge for PT scheme participants. Springer-Verlag Berlin Heidelberg, 2015 Organochlorine pesticides nationallicence Proficiency testing nationallicence Limited number of participants nationallicence Trace levels nationallicence E n number nationallicence Zeta -score nationallicence Prevoo-Franzsen Désirée National Metrology Institute of South Africa (NMISA), Lynnwood Ridge, Pretoria, South Africa aut Nhlapo Nontete National Metrology Institute of South Africa (NMISA), Lynnwood Ridge, Pretoria, South Africa aut Quinn Laura National Metrology Institute of South Africa (NMISA), Lynnwood Ridge, Pretoria, South Africa aut Fernandes-Whaley Maria National Metrology Institute of South Africa (NMISA), Lynnwood Ridge, Pretoria, South Africa aut Accreditation and Quality Assurance Springer Berlin Heidelberg 20/4(2015-08-01), 273-280 0949-1775 20:4<273 2015 20 769 https://doi.org/10.1007/s00769-015-1122-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00769-015-1122-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Prevoo-Franzsen Désirée National Metrology Institute of South Africa (NMISA), Lynnwood Ridge, Pretoria, South Africa aut NATIONALLICENCE 700 1- Nhlapo Nontete National Metrology Institute of South Africa (NMISA), Lynnwood Ridge, Pretoria, South Africa aut NATIONALLICENCE 700 1- Quinn Laura National Metrology Institute of South Africa (NMISA), Lynnwood Ridge, Pretoria, South Africa aut NATIONALLICENCE 700 1- Fernandes-Whaley Maria National Metrology Institute of South Africa (NMISA), Lynnwood Ridge, Pretoria, South Africa aut NATIONALLICENCE 773 0- Accreditation and Quality Assurance Springer Berlin Heidelberg 20/4(2015-08-01), 273-280 0949-1775 20:4<273 2015 20 769