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

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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

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Proficiency Testing Programme:

Presented as a Interlab Calibration Exercise 4 exercises per annum

3 - formulated product 1 - calculation exercise

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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

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THANK YOUTHANK YOU