AS/NZS 1605.3:2018 pdf download.Section 16 determin of permethrin in timber extracts – hplc analysis.
17.1 PRINCIPLE
Timber samples are extracted with acidified-methanol. After solvent evaporation under vacuum and addition of water, the extracts are fractionated on Amberlite XAD-4 to remove resinous substances. Samples are then combined with an internal standard and imidacloprid is quantilated by reverse-phase high-performance liquid chromatography.
17.2 REAGENTS
All reagents shall be of analytical quality. Unless otherwise specified. water used for the preparation of reagents shall be distilled water.
The following reagents shall be used:
(a) Mobile phase A ASTM type 2 water adjusted to pH 3 with phosphoric acid.
(b) Mobile phase B Methanol for IIPLC.
(c) imidacloprid Imidacloprid (99.9%. Bayer).
(d) Stock imidacloprid standard Weigh to the nearest 0.1 mg approximately 0.0 10 g imidacloprid [Item (c)]. dissolve in methanol and make up to 100 mL with methanol in a volumetric flask.
(e) Stock internal standard Weigh approximately 0.030 g etofenprox. dissolve in methanol and make up to 100 inL with methanol in a volumetric flask.
(f) 0.1 M sulphuric acid Prepare from sulphuric acid 9X% (conc.).
(g) Fiher (lid Celite 545.
(h) A,nberl ire XAD-4 20—50 mesh.
17.3 SAMPLING AND MOISTURE CONTENT
Timber shall be at least air-dry. and preferably at equilibrium moisture content. Samples to
be analysed shall not be oven-dried.
The timber shall be ground to pass through a 3 mm screen (e.g. Wiley Mill).
To determine moisture content, accurately weigh a sample, dry overnight at 105°C’. cool the dried sample in a desiccator then reweigh.
17.4 PROCEDURE
17.4.1 Sample preparation
The sample shall be prepared as follows:
(a) Accurately weigh a sub-sample of air dry, ground timber (approximately 10 g) into a plastic bottle.
NOTE: For example. 400 ml polyethylene terephthalate hexagonal jar. Visy Industrial Plastics 0X3266.
(b) Add approximately 250 mL methanol and 5 mL 0.1 M sulphuric acid to the subsample, cap the bottle and soak at an ambient temperature for at least 3 h.AS/NZS 1605.3 pdf download.