WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
DATA SHEET ON PESTICIDES No. 58
Primary use: Insecticide
Chemical group: Pyrethroid
It must be noted that the issue of a Data Sheet for a
particular pesticide does not imply endorsement of the pesticide by
WHO or FAO for any particular use, or exclude its use for other
purposes not stated. While the information provided is believed to
be accurate according to data available at the time when the sheet
was compiled, neither WHO nor FAO are responsible for any errors or
omissions, or any consequences therefrom.
The issue of this document does Ce document ne constitue pas une
not constitute formal publication. Il ne doit faire
publication. It should not be l'objet d'aucun compte rendu ou
reviewed, abstracted or quoted résumé ni d'aucune citation sans
without the agreement of the l'autorisation de l'Organisation
Food and Agriculture des Nations Unies pour
Organization of the United l'Alimentation et l'Agriculture
Nations or of the World Health ou de l'Organisation Mondiale de
Organization. la Santé.
1. GENERAL INFORMATION
1.1 COMMON NAME: Cypermethrin (ISO, BSI and BPC)
IUPAC: (RS)-ý-cyano-3-phenoxybenzyl (1RS)-cis,trans-3-(2,2-
CAS No. 1: (RS)-cyano (3-phenoxyphenyl)methyl (1RS)-cis,trans-
CAS Reg. No.: 52315-07-8
Molecular formula: C22H19Cl2NO3 Molecular weight: 416.32
1.1.2 Synonyms: BarricadeR; CCN 52; CymbushR; ImperatorR;
KafilR; NRDC 149; OMS 2002; PP 383; RipcordR; WL 43467
1.2 SYNOPSIS: Cypermethrin is a composite pyrethroid; a broad
spectrum, non-cumulative insecticide; and, a fast-acting
neurotoxin with good contact and stomach action. It is of
moderately high toxicity to mammals and readily metabolized with
immediate loss of activity. Cypermethrin is not a plant systemic,
it is readily degraded on soil or plants but has good residual
activity on inert surfaces.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics - The pure isomers are colourless
crystals, the technical material is a viscous yellow-brown
semi-solid. The melting points are 60-80°C.
1.3.2 Solubility - In water at 21°C, 0.01-0.2 mg/l; in hexane at 20°C,
103 g/l; soluble in acetone, cyclohexane, ethanol, xylene and
1.3.3 Stability - Cypermethrin is quite stable at temperatures under
220°C; photodecomposition has been observed in field tests, with
no reduction in biological performance. The optimum stability
occurs at pH 4 while decomposition occurs under alkaline
1.3.4 Vapour pressure - 5.07 x 10-9 kPa (3.8 x 10-8 mmHg) at 70°C.
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY
1.4.1 Common formulations - Emulsifiable concentrates of various
concentrations, 25-400 g a.i./l; ULV for agronomic use, 10-75 g
a.i./l; for veterinary purposes, e.c. 25-200 g/l; and, wettable
powder at 125 g/kg.
1.4.2 Pests controlled - Active against a wide range of insect pests,
particularly leaf and fruit eating Lepidoptera, Coleoptera and
Hemiptera; cattle ectoparasites, sheep scab, lice and ked.
1.4.3 Use pattern - Cypermethrin may be applied to a wide range of
fruit, vegetables, vines, tobacco, and several non-food crops. It
should be applied when pests first appear at rates of 25-150 g
a.i./ha. For Hemiptera control, foliar or soil treatment at 100
g/ha is effective. For cattle use 150 mg/l baths and for sheep
10 mg/l dips may be used. Good control of biting insects may
also be maintained by direct spraying of the animals or the
structural surfaces of animal housing.
1.4.4 Unintended effects - No cases of phytotoxicity have been
1.5 PUBLIC HEALTH USE - Cypermethrin may be used by professional
sprayers to control nuisance and disease vector insects in limited
1.6 HOUSEHOLD USE - No recommended use.
2. TOXICOLOGY AND RISKS
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption route - Cypermethrin is primarily absorbed from the
gastrointestinal tract. It may a so be absorbed by inhalation of
spray mist and only minimally through the intact skin.
2.1.2 Mode of action - Cypermethrin is a synthetic pyrethroid and a
permethrin analogue. This group of chemicals acts primarily on
the basal ganglia of the central nervous system, causing
repetitive nerve action through prolongation of sodium
permeability during the recovery phase of the action potential of
2.1.3 Excretion - The metabolism and elimination of cypermethrin have
been extensively studied in rats and mice and to some extent in
dogs and cows. Both isomers are readily metabolized by liver
microsomal esterases and oxidases. The cis-isomer is the more
stable of the two and may undergo extensive hydroxylation prior
to ester cleavage. In most animals, except dogs, urine was the
major route of elimination (+80%); the faecal route was less
important; the skin and pulmonary routes were not significantly
involved. The ester cleavage yielded cyclopropanecarboxylic acid
and 3-phenoxybenzoyl alcohol fragments. The latter was oxidized
to 3-phenoxybenzoic acid (3-PBA) and partially hydroxylated at
position 4', and to a lesser extent at 5- and 6-sites. The major
urinary excretion products in most species were 3-PBA as a free
acid and as conjugates of glucuronic and amino-acids; 4'-HO-3-PBA
as a free acid and as sulfates and glucuronides. The acid moiety
is primarily excreted as a free acid and also as a glucuronide
following oxidation at the methyl sites and lactone
rearrangement. The cyano group was relatively slowly excreted; a
small amount as an imino-thiazolidine-4-carboxylic acid salt was
rapidly excreted. In dogs, over 80% of the ingested dose was
found in the faeces indicating possibly poor absorption. In rats
and mice, only a small amount of unhydrolysed product was found
in faeces. Elimination of cypermethrin was rapid in most animals,
in most tissues the half-life was approximately one day; in
adipose tissue it ranged from 10 to 30 days.
2.1.4 Toxicity, single dose - The toxicity of cypermethrin varies
with the type of vehicle used, aqueous suspensions in general
were the least toxic and non-polar solutions the most toxic (e.g.
in corn oil the mouse LD50 is 82 mg/kg bw and for aqueous
suspensions it is over 750 mg/kg bw). Also, since the cis-isomer
is almost 10 times as toxic as the trans-isomer the acute
toxicity of a mixture will be determined by the isomer ratio.
Oral LD50: Technical material
Rat (M, F) 303 mg/kg bw (cis:trans, 50:50, in dimethyl-sulfoxide)
Mouse (M, F) 138 mg/kg bw (cis:trans, 50:50, in dimethyl-sulfoxide)
Rabbit (F) +2400 mg/kg bw (cis:trans, 40:60, undiluted)
Syrian (M, F) +400 mg/kg bw (cis:trans, 50:50, in corn oil)
Chinese (M, F) 203 mg/kg bw (cis:trans, 50:50, in corn oil)
Guinea-pig (M, F) 500-1000 mg/kg bw (cis:trans, 50:50, in corn oil)
Rat (F) +4800 mg/kg bw (cis:trans, 40:60, undiluted)
Rat (M, F) +1600 mg/kg bw (cis:trans, 50:50, in xylene)
Rabbit (F) +2400 mg/kg bw (cis:trans, 40:60, undiluted)
Rat (F) +500 mg/kg bw (cis:trans, 40:60, aqueous suspension)
Mouse (M, F) 485 mg/kg bw (cis:trans, 50:50, corn oil)
In general pyrethroid poisoning is characterized by hyperactivity
and hypersensitivity (somatosensory). Cypermethrin in particular
is included among a group of compounds producing the CS-syndrome
in rodents, in sequence: pawing and burrowing behaviour,
salivation, coarse tremors progressing to choreoathetosis and
occasionally terminal clonic seizures. Most susceptible species
possibly the mouse.
2.1.5 Toxicity, repeated doses:
Oral: Studies on rats (25-200 mg/kg bw per day for five days) and
hamsters (5-30 mg/kg bw per day for five days) confirmed the
pattern of clinical signs of toxicity observed in single dose
studies. These animals recovered within three to four weeks
after the initial treatment. Hamsters showed fur loss and dermal
ulceration in the early stages of the study. Further findings
are discussed in section 2.1.7 Neurotoxicity.
Dermal: There was a 20-30% mortality rate among rats given five
consecutive doses at 2500 and 5000 mg/kg bw per day. Clinical
signs of toxicity and sciatic nerve degeneration were consistent
with the observations in oral studies.
Cumulation of compound: The slow clearance rate from adipose
tissue after a single dose suggests a potential for
bioaccumulation in that tissue. Other body tissues do not appear
to accumulate cypermethrin.
Cumulation of effect: No information available.
2.1.6 Dietary studies
Short-term: Male and female rats were fed 92% cypermethrin (44:56
cis:trans) at concentrations of 0, 75, 150 or 1500 mg/kg of diet
for 90 days. No deaths occurred at any dose level. At the
highest dose there was an initial decrease in growth rate and
food consumption which returned to normal after four weeks.
Increased hepatic microsomal oxidation activity was observed in
females at the highest dose and in males at the two highest
doses; complete recovery occurred in both sexes by the fourth
week after treatment ended. Female rats showed a dose-dependent
decrease in kidney weight which was significant at the highest
dose only. No treatment-related gross or microscopic
abnormalities were observed in any body tissues or organs
(including the sciatic nerve) at any dose level.
In a second study, rats were fed cypermethrin (50:50) at 0, 25,
100, 450 or 1600 mg/kg of diet for 90 days. Mortalities occurred
among the males up to the fifth week at the highest dose level.
All the animals showed severe signs of neurotoxic poisoning at
this dose but the survivors progressively improved over the
remaining weeks of treatment. Severe sciatic nerve damage was
seen in all of the rats that died during treatment; the survivors
showed no such effect after 90 days of treatment. At the highest
dose level growth rates and food consumption declined; in
haematology - PCV and erythrocyte counts declined, especially
among the females. No consistent treatment-related adverse
effects were observed at or below the 100 mg/kg diet level.
The cypermethrin no-effect-level for rats was observed to be 5.0
mg/kg bw per day.
In an additional experiment male and female rats were fed either
the trans-isomer (at 0, 30, 100, 300, 750 or 1500 mg/kg of diet)
or the cis-isomer (at 0, 30, 100, 300, 750 or 1500 mg/kg of diet)
for 35 days. No mortalities occurred on the trans-isomer diet
while the cis-isomer caused extensive mortalities at the highest
dose. No treatment-related clinical signs of neurotoxic
poisoning were observed in the trans-isomer treated group. Growth
rates and food consumption declined while kidney and liver
weights increased at the highest dose. The cis-isomer treated
rats showed severe signs of neurotoxic poisoning at the two
highest doses. The dead rats showed extensive coagulative
necrosis of hepatocytes and severe sciatic damage. No central
nervous system damage was observed at any dose level of either
Male and female dogs were fed cypermethrin at 0, 5, 50, 500 or
1500 mg/kg of diet for 90 days. There were no mortalities. At
the 1500 mg/kg dose, significant signs of toxicity were observed
including diarrhoea, anorexia, tremors, ataxia, incoordination
and hyperesthesia. There were no consistent treatment-related
adverse effects at 500 mg/kg and below, and no adverse effects
were observed at 50 mg/kg. No compound-related gross or
histopathological changes were found at any dose level.
The cypermethrin no-effect-level for dogs was observed to be 1.25
mg/kg bw per day.
Long-term: Male and female rats were fed cypermethrin
(50:50 cis:trans) in the diet at 0, 1, 10, 100 or 1000 mg/kg of
diet for two years. There were no treatment-related mortalities
over the course of the study. At the highest dose level, the
growth rate and food consumption were depressed and the liver
weight increased. There were no clinical signs of toxicity, no
evidence of clinical neuropathy or histological evidence of nerve
degeneration. Chronic nephrosis was common to animals of all
dose groups but was not dose-related. The incidence of tumours
in the treatment groups was not significantly greater than in the
The cypermethrin no-effect-level for rats was observed to be 5.0
mg/kg bw per day.
2.1.7 Supplementary studies of toxicity
Carcinogenicity: There was no evidence of increased incidence of
tumours in a single long-term cypermethrin diet study in rats.
This finding is supported by those of several special studies for
teratogenicity in a mouse standard host-mediated assay, several
microorganism assays with and without rat liver microsomal
activation, and a hamster chromosomal damage assay.
Teratogenicity: No evidence of teratogenic potential was
observed in rats and rabbits given doses of up to 70 mg/kg bw per
day from day 6 to day 15 of gestation in rats or 30 mg/kg bw per
day from day 6 to day 18 of gestation in rabbits.
Reproduction: In two dominant lethal assays in mice there was no
observed dose-related evidence of either reduced implantations or
increased foetal deaths. No gross or microscopic abnormalities
of the testes and epididymes were observed in the treated males.
In a three-generation study, following cypermethrin
administration at concentrations up to 500 mg/kg of diet, no
adverse effects on reproductive behaviour, fertility, gestation,
viability or lactation were observed.
Mutagenicity: Cypermethrin (with and without rat liver microsomal
activation) was not observed to be genetically active in a
mitotic gene conversion assay with S. cerevisiae; in a mutation
rate assay with E. coli and S. typhimurium (TA-1538) at 500
mg/plate doses; in a revertant gene assay with S. typhimurium
(TA-1535, -1537, -1538, -98 and -100) at 1 mg/plate doses; and,
in a mouse host-mediated assay with S. cerevisiae at 25 and 50
mg/kg bw given orally. It was also observed to be inactive in a
Chinese hamster chromosomal damage assay at 20 and 40 mg/kg bw,
Neurotoxicity: Cypermethrin administered orally to rats and
hamsters in high acute and subacute doses produced reversible
clinical signs of ataxia, behaviour changes and, histological and
chemical changes consistent with Wallerian degeneration. Doses
below the lethal range did not produce lesions in the sciatic and
posterior tibial nerves. There was no evidence of delayed
neurotoxicity in hens given 1.0 mg/kg bw doses of cypermethrin.
Primary irritation and sensitization: Moderate skin irritation
and mild eye irritation were produced by single applications of
undiluted technical cypermethrin in rabbits. Cypermethrin was
also observed to have a weak sensitization potential in
Cardiovascular and respiratory system: Cypermethrin was observed
to attenuate the reflex control of respiration and the autonomic
control of circulation.
Metabolism: Cypermethrin did not induce either cytochrome P-450
or NADPH cytochrome C reductase activity in hepatocytes of male
Long-Evans rats following 50 mg/kg bw per day, orally for up to
2.1.8 Modification of toxicity - Substances which depress or inhibit
liver microsomal enyzme activity will increase the toxicity of
cypermethrin, in particular, profenfos, sulprofos and DEF
significantly synergize the cis-isomer on cabbage looper larvae
and adult house flies.
2.2 TOXICOLOGY - MAN
2.2.1 Absorption - Cypermethrin is primarily absorbed from the
gastrointestinal tract. It may also be absorbed by inhalation of
spray mist and only minimally through the intact skin.
2.2.2 Dangerous doses
Single: No information.
Repeated: No information.
2.2.3 Observations on occupationally exposed workers - Urinary levels
of cyclopropanecarboxylic acid metabolite in spraymen during one
experimental spray trial were observed to be 0.4 µg/ml or less.
In another trial, operators spraying with hand-held ULV apparatus
were found to have measurable cypermethrin residues on the
exposed parts of their bodies. They showed no adverse effects.
The rate of dermal exposure ranged from 1.5 to 4.6 mg/hour, the
24 hour urine metabolite level was between 0.05 and 0.32 mg for
most subjects. An estimate of approximately 3% of the total
dermal dose was absorbed and rapidly excreted.
2.2.4 Observation of the general public - No information available.
2.2.5 Observation of volunteers - No information available.
2.2.6 Mishaps - No information available.
2.3 TOXICITY TO NON-MAMMALIAN SPECIES
LC50 (96 hr): Salmon 2.0 µg/l technical
Brown trout 2.4 µg/l technical
Lethal threshold Salmon 2 .4 µg/l technical
LC50 (24 hr): Rainbow trout 25.0 µg/l technical
Rainbow trout 61.0 µg/l 40% a.i. fomulated
Oral LD50: Chicken (M, F) +2000 mg/kg bw
Partridge (M, F) +3000 mg/kg bw
2.3.3 Other species - Cypermethrin is relatively toxic to bees.
LC50 (9 hr): Lobster 0.04 µg/l
Shrimp 0.01 µg/l
3. FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON REGULATION OF
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY (For definition of
categories, see the Introduction to data sheets)
There are no solid formulations available.
Liquid formulations over 15%, Category 3.
Other liquid formulations, Category 4.
3.2 TRANSPORTATION AND STORAGE
Formulations in categories 3 and 4 - Should be transported or
stored in clearly labelled rigid and leakproof containers and away
from containers of food and drink. Storage should be under lock
and key and secure from access by children and other unauthorized
Formulations in categories 3 and 4 - Full protective clothing (see
part 4) should be used by those handling concentrates. Adequate
washing facilities should be available at all times and should be
close to site of handling. Eating, drinking and smoking should be
prohibited during handling and before washing after handling.
3.4 DISPOSAL AND/OR CONTAMINATION OF CONTAINERS
Formulations in categories 3 and 4 - Containers must be either
burned or crushed and buried below topsoil. Care must be taken to
avoid sudsequent contamination of water-sources. Containers may
be decontaminated (for method see paragraph 4.3 in part 4).
Decontaminated containers should not be used for food and drink.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
Formulations in categories 3 and 4 - Workers suffering from
asthma, allergies and other respiratory disorders, and
cardiovascular disorders should be excluded from contact. Persons
under medication with neuroactive drugs should avoid contact.
Special account should be taken of the workers' ability to
comprehend and follow instructions. Training of workers in
techniques to avoid contact is essential. Pre-employment and
periodic medical examinations are not required.
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT
All formulations - Pilot and loaders should have special training
in application methods and early symptoms of poisoning. Flagmen,
if used, should wear overalls and be located well away from the
Formulations in categories 3 and 4 - Minimum cautionary statement
- "WARNING - POISON" (skull and cross-bones insignia).
Cypermethrin is a pyrethroid pesticide; it may be poisonous if
swallowed. It may be inhaled as a dust or mist and it may be
irritating to the skin and eyes. Avoid skin contact. Wash
thoroughly with soap and water after using the product. Keep the
material out of reach of children and well away from foodstuffs,
animal feed and food containers. If poisoning occurs, call a
physician. There are no specific antidotes.
3.8 RESIDUES IN FOOD
Maximum residue levels - Maximum residue levels have been reco-
mmended by the Joint FAO/WHO Meeting on Pesticide Residues.
4. PREVENTION OF POISONING IN MAN AND EMERGENCY AID
4.1 PRECAUTIONS IN USE
4.1.1 General - Cypermethrin is a pyrethroid, and a neurotoxic agent of
variable toxicity to mammals depending on the vehicle. It is
readily absorbed from the gastrointestinal tract; it may be
absorbed by inhalation of dust and fine spray mist but only
minimally through the intact skin. The health hazard is
considerably diminished by the low concentrations of the active
ingredient in all formulations. It is important that
concentrated formulations be washed immediately from the skin and
4.1.2 Manufacture and formulation - TLV - No information. Closed
systems and forced ventilation may be required to reduce, as much
as possible, the exposure of workers to the chemical.
4.1.3 Mixers and applicators - When opening a container and mixing,
protective impermeable boots, clean overalls impermeable gloves,
eye protection and a respirator should be worn. Mixing, if not
mechanical, should always be carried out with a paddle of
appropriate length. Avoid contact to mouth and eyes. Before
eating, drinking or smoking, hands and other exposed skin should
be thoroughly washed with alkaline soap.
4.1.4 Other associated workers (including flagmen in aerial operations)
- Persons exposed to the compound and associated with its
application should use good footwear and clean overalls, with
head covers if indicated.
4.1.5 Other populations likely to be affecteed - With good agricultural
practice, subject to section 4.2 below, other populations are
not likely to be exposed to hazardous amounts of the compound.
4.2 ENTRY OF PERSONS INTO TREATED AREAS - Though cypermethrin is
relatively persistent, low application rates ensure low residue
levels. Unprotected persons may enter treated areas immediately
after spraying without being exposed to hazardous amounts of
4.3 SAFE DISPOSAL OF CONTAINERS AND SPILLAGES - Residues in
containers should be emptied in a diluted form into a deep pit
taking care to avoid ground waters. The empty container may be
decontaminated by rinsing two or three times with water and
detergent and scrubbing the sides. The hands should be protected
during this work. Decontaminated containers should not be used
for food and drink.
4.4 EMERGENCY AID
4.4.1 Early symptoms of poisoning - Based on animal studies, these may
include excessive salivation, nausea ana vomiting; shortness of
breath and laboured breathing; coarse tremors, hypersensitivity
to external stimuli and general weakness; a burning or itching
sensation following contact; hypotension and slow heart rate.
These may be followed by hypertension, increased heart rate and
convulsive muscle contractions.
4.4.2 Treatment before person is seen by a physician, if these symptoms
appear following exposure - The person should stop work
immediately, remove contaminated clothing and clean the affected
skin area. First soak up any liquid remaining on the skin with
readily disposable material (e.g. talcum powder or absorbent
cloth or paper), wash the affected area with warm water and
alkaline soap. For eye contamination, wash with copious amounts
of water. Avoid exposing affected skin or eyes to bright light.
If the material was swallowed and signs of toxicity are severe,
induce vomiting if person is conscious and aspiration of vomit
can be avoided. In the event of collapse, apply artificial
respiration. Keep in mind that if mouth to mouth respiration is
used, vomit may contain toxic amounts of cypermethrin. Keep the
person calm and comfortable.
5. FOR MEDICAL AND LABORATORY PERSONNEL
5.1 MEDICAL DIAGNOSIS AND TREATMENT OF POISONING
5.1.1 General information - Cypermethrin is a pyrethroid pesticide of
moderate toxicity to mammals. It is readily absorbed from the
gastrointestinal tract, by inhalation of dust and fine spray mist
and only minimally through the intact skin. The hydrolysis and
oxidation products of metabolism are rapidly excreted in the
urine and faeces. Cypermethrin is a neurotoxic agent most
probably acting through the central nervous system to cause
repetitive nerve activity.
5.1.2 Signs and symptoms - Little information is available on the acute
toxic effects of pyrethroids in humans. Based upon animal
studies, high doses may cause repetitive activity in sensory and
motor nerves. Early signs of poisoning may be: salivation,
irritability, tremors and ataxia; respiratory and cardiovascular
dysfunction may also occur. In man, a burning and itching
sensation sometimes follow contact.
5.1.3 Laboratory - There are no established practical methods for
determining pyrethroids in body fluids. Urinary levels of 3-
phenoxybenzyl degradation products may be a useful index of
exposure. In addition, the monitoring of sensory nerve action
potential and central nervous and cardiac activities (EEG and
ECG) may be useful in diagnosis and in assessment of therapy.
5.1.4 Treatment - There is no specific antidote, treatment must be
symptomatic. Keep the patient warm and calm. In cases of severe
intoxication, therapy should include a sedative and
anticonvulsant (e.g. barbiturates, diazepam, paraldehyde, etc.).
The use of antispasmodic drugs is of limited value; mephenesin
and atropine have been found to effectively alleviate the
symptoms of pyrethroid poisoning in laboratory animals. If a
large quantity of the compound has been swallowed, unless the
patient is vomiting, gastric lavage should be performed using a
5% sodium bicarbonate solution, followed by powdered activated
charcoal. For skin contact, soak up any liquid remaining on skin
with readily disposable absorbent material then wash the affected
area with warm water and alkaline soap. If skin irritation
occurs treat with a soothing skin cream and avoid exposure to
direct light. For eye contamination, wash the eye with 4% sodium
bicarbonate or any other non-irritating, alkaline aqueous
5.1.5 Prognosis - There have been no reports of overt symptoms
resulting from poisoning of man by cypermethrin; the prognosis
therefore is not known. However, by analogy with laboratory
animals, it may be assumed that if the acute toxic effect is
survived the chances of complete recovery are good.
5.1.6 References to previously reported cases - No information.
5.2 SURVEILLANCE TESTS - None
5.3 LABORATORY METHODS - References only are given.
5.3.1 Detection and assay of compound and residues - Chapman, R. A. &
Harris, C. R. (1978) Journal of Chromatography, 166(2), 513-516.
Papadopoulou-Mourikidou, E., Iwata, Y. & Gunther, F. A. (1981)
J. Agric. Food Chem., 29(6), 1105-1111. Siltanen, H. &
Rosenberg, C. (1980) Publ. State Inst. Agric. Chem. (Finland),
Vol. 17, 61 pp.