Transcript Development, Publication and Use of CIPAC

Sampling of Pesticide Active
Ingredients and Formulations
for Quality Control
M. D. Müller
Training course on quality control of pesticides,
DoA, Thailand July 2012
What is the main goal
• To produce a sample which is
representative for the whole
consignment in a well documented way
for quality control in the laboratory
For representative sampling
prior knowledge of a.i. or
formulation is required
Some a.i. and formulations tend to be
inhomogenous:
• Semi-crystal a.i. tend to selective
crystallization
• Liquid formulations tend to unmix (not true
solutions)
• Solid formulations tend to segregate
Sampling operations often require
handling of formulations in the field..
• Avoid sampling in the field wherever
possible and collect whole bottle to
sample in lab
• There exist protocols for field sampling
Sampling Protocol of BVL, Germany
(www.bvl.bund.de)
• If possible, samples are collected in original packaging
if possible (up to 5 kg or L)
• Larger size: subsampling in the field:
for solid formulations: homogenize 3 subsamples
for liquid formulations: homogenize as end-user would
do (stir, roll etc.)
Minimal amount: 600 ml for liquid and 1800 g for solid
formulations
Use sampler and bottles which are inert, store in a cool,
dry and dark place and ship to lab together with protocol
Sampling Protocol of US EPA*
*http://www.epa.gov/oecaerth/resources/publications/monitoring/fifra/manuals/fifra/fifr
amanappx_a.pdf
SUB-SAMPLING
FORMULATION PESTICIDES
Liquid Formulations
Review the label for personal safety equipment
requirements and if manufacturers' instructions
include shaking before use. If so, be sure material is
thoroughly mixed before opening the container. Put
on required safety equipment.
Note: Do not attempt to agitate containers larger than 5
gallons.
Dry Materials (Dusts and Granular
Formulations)
• Cut a V-shaped slit on the side or flat surface of the
bag where writing is not found. Note: Use only a
clean knife for cutting the slit. NEVER use a pocket
knife used for other purposes.
• Insert a clean unused plastic tube diagonally through
the bag, when obtaining the sample, not just from
one location in the bag.
• Carefully remove and fill a sample bottle/can with the
material and identify the sample with the inspector’s
initials, the sample number, date, etc. on the side of
the bottle/can.
Sampling Protocol of FAO in Appendix
1 in FAO/WHO Manual
• For
technical materials (TC)
• For liquid formulations
• For solid formulations
Technical material
7.1 TECHNICAL GRADE ACTIVE INGREDIENTS
Where the technical grade active ingredient is transported or
stored in a single, large bulk, 15 primary samples should be
taken from randomly selected parts of the batch.
The minimum mass of the bulk sample should be 300 g and
3 equal laboratory samples should be withdrawn from it after
mixing: one to be sent to the testing laboratory, (..)
Note Bulk samples and laboratory samples of technical
grade active ingredients must be made homogeneous, as
far as is practicable, before subdivision. In order to facilitate
homogenization of laboratory samples, liquid pesticides may
be carefully warmed to a maximum of 40°C, in the
laboratory. Warming of bulk samples in the field should not
be attempted.
7.2.1 LIQUID FORMULATIONS (SOLUTIONS, EMULSIFIABLE
CONCENTRATES, SUSPENSION CONCENTRATES, EMULSIONS)
Using appropriate care, containers which are to be opened for sampling
should be shaken, rolled, tumbled or otherwise agitated (using methods
which could be adopted by end users) before sampling, to try to achieve
physical homogeneity. Before taking samples, the contents of containers of
liquid pesticides should be visually checked, where practicable, for any
physical heterogeneity, such as crystallization, precipitation, sedimentation
or separation. A rod may be used to check for the presence of dense
sediment. After complete or partial emptying, inspect containers again for
sediment which was not re-suspended.
Where the separated components of formulations cannot be redissolved or
homogenized by methods which can also be used in the field before
application of the formulation, this must be recorded in the sampling report.
Note Such a formulation is not suitable for use and separate samples
should be taken from the segregated portions as evidence of the
deteriorated condition (...)
7.2.2 PARTICULATE SOLIDS (DUSTS, DISPERSIBLE POWDERS,
WATER DISPERSIBLE GRANULES, GRANULAR FORMULATIONS)
(..). A batch that has been stored in an exposed state (e.g. in
inadequately sealed bags) must be regarded as non-uniform and
the number of bulk samples taken should be in accordance with
Table 1.
Granular formulations (especially those such as GR, WG, SG etc.)
may undergo mechanical segregation of the different particle sizes
during transport and when being transferred to other containers. At
the initial sampling and when samples are subdivided for preparing
the laboratory sample and analytical portions, the utmost care must
be exercised to obtain a representative portion of the material.
Where applicable, CIPAC methods MT 58.1 and MT 166, should
be used for sampling solids. Otherwise, bags may be sampled
through a top corner.
CIPAC Methods
CIPAC analytical methods do give detailed
instruction on sampling in laboratory and
subsampling for analysis of potentially
inhomogeneous active ingredients and formulations
as for cypermethrin
Specific Methods for Sampling MT 58.1
MT 166
Conclusions and recommendations
• There exist several sampling guidelines which are at
least partially useful
• Sampling in the field has a high probability to alter
some characteristics of the pesticide and should be
restricted to situations where unavoidable (hygiene,
changing pesticide quality in uncontrollable way)
• If not yet available, a suitable Manual for Inspection
Service in Thailand and training of personnel for
sampling is recommended
Thank you for your attention!