SOUTH AFRICAN BUREAU OF STANDARDS
PRESENTED BY:PRESENTED BY:
SUSAN M. MARAISSUSAN M. MARAIS
Proficiency Testing Proficiency Testing on Pesticide on Pesticide
Formulations in Formulations in South AfricaSouth Africa
SOUTH AFRICAN BUREAU OF STANDARDS
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OBJECTIVESISO Guideline 43:
determine the performance of a Lab and to monitor the
continuing performance of a Lab
identify problems in a Lab and initiate remedial actions
establish the effectiveness and comparability of new test
methods
to prove integrity and give additional confidence to clients
to determine the performance characteristics of a method
SOUTH AFRICAN BUREAU OF STANDARDS
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Proficiency Testing Programme:
Presented as a Interlab Calibration Exercise 4 exercises per annum
3 - formulated product 1 - calculation exercise
SOUTH AFRICAN BUREAU OF STANDARDS
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PROGRAMME HISTORY
Initiated during the early 1980's 71 exercises specially prepared test items
active ingredient content HPLC / GLC
effectiveness of the formulationeg. suspensibility, emulsion stability, density, foaming, wettability, viscosity, flashpoint, moisture content ect.
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PARTICIPATING LABORATORIES Participants
Private sector (contract labs) Government labs Semi-state institutions QA labs of Manufacturers
12 to 14 labs - 8 to 9 labs Participation under Code
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EVALUATION OF RESULTS Difficult to evaluate Physical Test determinations
CIPAC methods Specially prepared Reporting Forms
Active ingredient determinations Triplicate Submit chromatograms
Specialist Technical Committee (STC)
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FEEDBACK
Identify all errors Feedback letter to Lab Manager Certificate for Successful Participation South African National Accreditation
Body (SANAS)
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TRAINING NEEDS
Physical Test Results Workshop Continuous training
Calculations
Calculation ICE’s
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Involvement of External Organizations
Government Departments
Agriculture
Health
Agricultural and Veterinary Chemicals
Association of South Africa (AVCASA)
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STATISTICAL EVALUATION
Small number of participants
Statistical methods – not very successful
Mean results of a.i. content used as real
value – obvious outliers excluded
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MARGIN OF ACCEPTABILITY
Amount active ingredient measured Deviation
Less than 25g/kg()More than 25g/kg(), but less than 100g/kg()More than 100g/kg(), but less than 250g/kg()More than 250g/kg(), but less than 500g/kg()More than 500g/kg()
± 15%
± 10%
± 6%
± 5%
± 2.5%
Analyst, September 1985, vol. 110
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LAB CODE
1ST RESULT 2ND RESULT 3RD RESULT MEAN
129.20 129.20 130.24 129.55 g/ A
129.63 130.13 129.78 129.84 g/
129.77 130.2 129.80 129.92 g/
129.78 130.22 129.94 129.98 g/
129.91 130.25 130.03 130.06 g/
129.74 129.44 129.91 129.70 g/
B
129.67 130.11 129.83 129.87 g/
C 259.72 260.26 259.55 259.69 g/
G 1.28 1.30 1.31 1.30 g/
H 127.82 130.15 130.62 129.53 g/
L 129.78 130.22 129.94 129.98 g/
RESULTS: CALCULATION ICE 1/2004F (Triclopyr)
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Results: ICE 2/2004F Acetochlor EC
C - Emulsion completeCr/o - Cream or oil on top of the EmulsionF - FoamS - Sediment
Lab codeA.i g/l
Physical Tests
Emulsion stability Densityg/ml
Initial
C F
After 30 min
Cr/o F S
After 24 h & 10 inversions
Cr/o F S
A 786.8 N 0 0 4 0 0 4 0 1.095
B 803.8 - - - 1.09
C 759.0 N 0 0 10 1 0 8 0 1.070
E 799.1 N 0 0 0 0 0 0 0 1.109
F 789.5 N 0 0 2 0 0 1 0 1.09
H 728.9 N 1 1 10 0 0 10 0 1.101
L 776.7 N 2 0 10 0 0 10 0 1.094
Mean 775.0 2.5% High – 794.5 2.5% Low - 755.7
SOUTH AFRICAN BUREAU OF STANDARDS
THANK YOUTHANK YOU
