Presentation on theme: "SOUTH AFRICAN BUREAU OF STANDARDS PRESENTED BY: SUSAN M. MARAIS Proficiency Testing on Pesticide Formulations in South Africa."— Presentation transcript:
SOUTH AFRICAN BUREAU OF STANDARDS PRESENTED BY: SUSAN M. MARAIS Proficiency Testing on Pesticide Formulations in South Africa
SOUTH AFRICAN BUREAU OF STANDARDS 2 OBJECTIVES ISO Guideline 43: n determine the performance of a Lab and to monitor the continuing performance of a Lab n identify problems in a Lab and initiate remedial actions n establish the effectiveness and comparability of new test methods n to prove integrity and give additional confidence to clients n to determine the performance characteristics of a method
SOUTH AFRICAN BUREAU OF STANDARDS 3 Proficiency Testing Programme: Presented as a Interlab Calibration Exercise n 4 exercises per annum t 3 - formulated product t 1 - calculation exercise
SOUTH AFRICAN BUREAU OF STANDARDS 4 PROGRAMME HISTORY n Initiated during the early 1980's n 71 exercises n specially prepared test items t active ingredient content HPLC / GLC t effectiveness of the formulation eg. suspensibility, emulsion stability, density, foaming, wettability, viscosity, flashpoint, moisture content ect.
SOUTH AFRICAN BUREAU OF STANDARDS 5 PARTICIPATING LABORATORIES n Participants t Private sector (contract labs) t Government labs t Semi-state institutions t QA labs of Manufacturers n 12 to 14 labs - 8 to 9 labs n Participation under Code
SOUTH AFRICAN BUREAU OF STANDARDS 6 EVALUATION OF RESULTS n Difficult to evaluate Physical Test determinations t CIPAC methods t Specially prepared Reporting Forms n Active ingredient determinations t Triplicate t Submit chromatograms n Specialist Technical Committee (STC)
SOUTH AFRICAN BUREAU OF STANDARDS 7 FEEDBACK n Identify all errors n Feedback letter to Lab Manager n Certificate for Successful Participation n South African National Accreditation Body (SANAS)
SOUTH AFRICAN BUREAU OF STANDARDS 8 TRAINING NEEDS n Physical Test Results t Workshop t Continuous training n Calculations t Calculation ICE’s
SOUTH AFRICAN BUREAU OF STANDARDS 9 Involvement of External Organizations n Government Departments t Agriculture t Health n Agricultural and Veterinary Chemicals Association of South Africa (AVCASA)
SOUTH AFRICAN BUREAU OF STANDARDS 10 STATISTICAL EVALUATION n Small number of participants n Statistical methods – not very successful n Mean results of a.i. content used as real value – obvious outliers excluded
SOUTH AFRICAN BUREAU OF STANDARDS 11 MARGIN OF ACCEPTABILITY Amount active ingredient measured Deviation Less than 25g/kg(R) More than 25g/kg(R), but less than 100g/kg(R) More than 100g/kg(R), but less than 250g/kg(R) More than 250g/kg(R), but less than 500g/kg(R) More than 500g/kg(R) ± 15% ± 10% ± 6% ± 5% ± 2.5% Analyst, September 1985, vol. 110
SOUTH AFRICAN BUREAU OF STANDARDS 12 RESULTS: CALCULATION ICE 1/2004F (Triclopyr )
SOUTH AFRICAN BUREAU OF STANDARDS 13 Results: ICE 2/2004F Acetochlor EC C - Emulsion complete Cr/o - Cream or oil on top of the Emulsion F - Foam S - Sediment Lab code A.i g/l Physical Tests Emulsion stabilityDensity g/ml Initial C F After 30 min Cr/o F S After 24 h & 10 inversions Cr/o F S A786.8N 00 4 0 1.095 B803.8---1.09 C759.0N 00 10 10 8 01.070 E799.1N 00 0 0 1.109 F789.5N 00 2 00 1 01.09 H728.9N 11 10 00 10 01.101 L776.7N 20 10 0 1.094 Mean775.02.5% High – 794.5 2.5% Low - 755.7
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