Journal of Tropical Forest Sciences 5 (3): 342-352 342
DETERMINATION OF CYPERMETHRIN CONTENT IN
OSCILLATING PRESSURE TREATED RUBBERWOOD
Salamah Selamat, Wan Asma Ibrahim, Habibah Mohamad
Forest Research Institute Malaysia, Kepong, 52109 Kuala Lumpur, Malaysia
Universiti Pertanian Malaysia, 43400 UPM, Serdang, Selangor Darul Ehsan, Malaysia
Received August 1991
SALAMAH SELAMAT, WAN ASMA IBRAHIM, HABIBAH MOHAMAD & FAEZAH
ABOOD. 1993. Determination of cypermethrin content in oscillating pressure
treated rubberwood. Rubberwood samples at three different moisture contents were
treated with cypermethrin by oscillating pressure method. The amount of
cypermethrin in the wood was determined immediately after treatment and after
drying by calculation and by high performance liquid chromatography (HPLC).
Results showed that the amount of cypermethrin detected by HPLC was much lower
than that by calculation. Rubberwood samples of low moisture contents gave better
penetration of cypermethrin. Cypermethrin was detected only in the first layer
(1 cm) of the treated green samples at all drying conditions. For the samples treated
at lower moisture contents, cypermethrin was detected in all three layers taken.
However, the amount of cypermethrin detected decreased as the drying time
Key words : Rubberwood - oscillating pressure method - cypermethrin - HPLC
SALAMAH SELAMAT, WAN ASMA IBRAHIM, HABIBAH MOHAMAD & FAEZAH
ABOOD. 1993. Penentuan kandungan sipermethrin dalam kayu getah yang diawit
dengan kaedah tekanan berulang. Contoh kayu getah yang terdiri dari tiga kadar
kandungan kelembapan air yang berlainan diawet dengan bahan awet sipermethrin
menggunakan kaedah tekanan berulang. Kandungan sipermethrin di dalam kayu
berawet ditentukan sebaik sahaja selepas rawatan dan selepas dikeringkan dengan
cara kiraan dan kaedah kromatografi cecair berkuasa tinggi (High Performance
Liquid Chromatography, HPLC). Keputusan menunjukkan bahawa kandungan
sipermethrin yang dikesan dengan menggunakan kaedah HPLC lebih rendah dari
kaedah kiraan. Contoh kayu getah yang mempunyai kandungan kelembapan air
yang rendah menghasilkan penembusan sipermenthrin yang baik. Sipermethrin
juga dikesan hanya pada lapisan pertama (1 cm) pada semua contoh kayu yang
diawet dalam keadaan kelembapan tinggi pada semua keadaan kekeringan.
Sipermethrin dikesan pada kesemua lapisan (3 lapisan) dalam kayu yang diawet
dalam keadaan kelembapan air yang rendah. Walau bagaimanapun kandungan
sipermethrin yang dikesan berkurangan sekiranya masa kekeringan dipanjangkan.
Journal of Tropical Forest Science5 (3): 342-352 343
Boron treatment by the dip-diffusion and full-cell processes are two common
methods used for the protection of rubberwood against insects. Boron com-
pounds have been found to be suitable for the treatment of both green and
partially seasoned timber as they readily diffuse into the timber (Salamah et al.
1987, 1988). These compounds do not discolour wood but they readily leach
from the treated wood (Anonymous 1979, Zaitun & Salamah 1990). Due to this,
alternative insecticides such as synthetic pyrethroids have been tested for use in
Pyrethroids possess low mammalian toxicity and do not pose environmental
hazards. The compounds are strongly absorbed by soil and are non-leachable
and biodegradable (Briggs et al. 1983). Apart from being an agricultural insecti-
cide, pyrethroids have also been treated on logs and timbers (Berry 1979) and
have been found effective against marine borers (Rutherford et al. 1982), ter-
mites (Y oshimura et al. 1989) and wood boring insects (Baker & Berry 1980).
Oscillating pressure treatment is an effective method of treating timbers using
non-diffusible preservatives especially for refractory timbers (Wilkinson 1979).
This method has been practised in Malaysia for the treatment of rubberwood
with synthetic pyrethroids. However, the efficiency in terms of penetration and
retention of the compounds has not been assessed. The stability of the chemical
after penetration into the wood must be ensured for the treated wood to be
adequately protected during service. Its permanence inside the wood at various
stages of drying after treatment can be assessed by determining its retention
values. The results obtained can be used as a guideline to determine the required
concentration of the treatment solutions before treatment for various types of
The objective of this study was to assess the penetration and retention of
cypermethrin in rubberwood following treatment by the oscillating pressure
method (OPM) and to monitor the cypermethrin content at various stages of
drying after treatment.
Materials and methods
Preparation of rubberwood samples for treatment
In this study three sets of rubberwood samples dried at different conditions
were used as shown in Table 1. The sample size was 50 X 50 X 1200 mm. The
six replicates of the wood samples used for each drying of condition were
selected from a batch of 20 pieces. The samples selected were free from dirt, bark
and any natural or drying defects. The samples were end-coated with epoxy paint
and weighed before treatment.
Journal of Tropical Forest Sciences 5 (3): 342-352 352
HONG L.T., MOHD ALI SUJAN, TAN A.G. & SINGH K.D. 1982. Preservation and protection of
rubberwood against biodeteriorating organisms for more efficient utilisation. Malaysian
Forester 45(3) : 299 - 315.
OLIVEIRA, A.M.F. 1983. Laboratory tests on the residual effects of pyrethroids against termites after one year.
The International Research Group on Wood Preservation, Working Group 1. Termite
problems related to structure and products. (Document no : IRG/wp/1216).
RUTHERFORD, D., REAY, R.C. & FORD, M.G. 1982. The development of a screening method to
estimate contact toxicity of pyrethroids against wood-boring marine Crustaceae, Limnoria
spp. Pesticide Science 10 : 527-530.
SALAMAH SELAMAT, MOHD. DAHLAN JANTAN, HABIBAH MOHD & ZAITUN SAID. 1987.
Rubberwood preservation : dip diffusion treatment at varies moisture content. Pp. 257 - 260
in Proceedings Malaysian Chemical Conference. October 14 - 17, 1984. Kuala Lumpur.
SALAMAH SELAMAT, HABIBAH MOHD & ZAITUN SAID. 1988. Preservation of rubberwood by
boron-double vacuum process. Journal of Tropical Forest Science 1 (2) : 133-139.
WILKINSON J.G. 1979. Industrial Timber Preservation. Associated Business Press, London.
YOSHIMURA, T., TSUNODA, K. & NISHIMOTO, K. 1989. Effect of soil burial on termiticidal
performance of pyrethroids. Material und Organismen 24(3) : 227-238.
ZAITUN SAID & SALAMAH SELAMAT. 1990. Observation of insect attact on boron treated
rubberwood after 12 months outdoor and indoor exposure. Pp. 32 - 43 in Proceedings 1st.
Chemistry Division Seminar . FRIM, Kepong.