<<< Back to Sampling and Analytical Methods Link to Printing Instructions Printing Instructions

For problems with accessibility in using figures, illustrations and PDFs in this method, please contact
the SLTC at (801) 233-4900. These procedures were designed and tested for internal use by OSHA personnel.
Mention of any company name or commercial product does not constitute endorsement by OSHA.

Cypermethrin

Related Information: Chemical Sampling - Cypermethrin
Method no.: PV2063; Partially Validated

Control no.: T-PV2063-01-9306-CH

Matrix: Air

Target Concentration (TC): 1.0 mg/m3 with a skin notation (Arbitrary). There is no OSHA permissible exposure level (PEL) or ACGIH threshold limit value (TLV) for cypermethrin. 

Procedure: Samples are collected by drawing known volumes of air through OSHA versatile sampler (OVS-2) tubes. Each tube contains a glass fiber filter and two sections of XAD-2 adsorbent. Samples are desorbed with desorbing solution (see Section 3.2) and analyzed by gas chromatography (GC) using an electron capture detector (ECD). 

Recommended air volume and sampling rate: 60 L at 1.0 L/min 

Detection limit of the overall procedure (based on the recommended air volume and the analytical detection limit): 0.014 mg/m3

Status of method:  Partially evaluated method. This method has been partially evaluated and is presented for information and trial use only.

Special Requirement:  Sample should be refrigerated. 

June 1993 Chemist: Yogi Shah 



Organic Service Branch II 
OSHA Salt lake Technical Center 
Salt Lake City, Utah 



1. General Discussion
1.1 Background
1.1.1 History of procedure

This evaluation was undertaken to determine the effectiveness of the OVS-2 tube as a sampling device for cypermethrin. It follows the procedure developed for pyrethrum (Ref. 5.1).

1.1.2 Toxic effects (This section is for information only and should not be taken as the basis of OSHA policy)

Besides being absorbed following inhalation or ingestion, cypermethrin is readily adsorbed through the intact skin (Ref. 5.2). When a particular pesticide has a low dermal LD 501 a skin notation should be added to the TLV or PEL. Cypermethrin has an acute oral LD50, of 70 mg/Kg and acute dermal LD50 of 500 mg/Kg for rats (Ref. 5.4). Due to these factors an arbitrary target concentration of 1.0 mg/m3 with a skin notation, was chosen for cypermethrin.

1.1.3 Potential workplace exposure

Cypermethrin is an insecticide/pesticide used to control insects on ornamental plants, vegetables, fruits, farm crops, and on pets. Can also be used for termite control. No data is available on the extent of work place exposure (Ref. 5.3).

1.1.4 Physical properties (Ref. 5.3, 5.4 and 5.5)

CAS number: 52315-07-8
IMIS number: C628
Molecular weight: 416.3
Molecular formula: C22H19CL2NO3 
Melting point: 60 to 80C at 101.3 kPa (760 mmHg)
Solubility: insoluble in water 
soluble in methanol, acetone, xylene, methylene chloride
Synonyms: cypermethrin 
Chemical name: 3-(2,2-Dichloroethenyl)-2,2,-di- methylcyclopropanecarboxylic acid cyano (3-phenoxyphenyl) methyl ester
Trade names: Cypercopal, Cyperkill, Cyperma
Appearance: colorless crystals (pure isomer)
Structure:  Structure
 
1.2 Limit defining parameters 

The detection limit of the analytical procedure, including a 11:1 split ratio, is 0.012 ng per injection. This is the amount of analyte which will give a peak whose height is approximately five times the baseline noise. 
2. Sampling Procedure
2.1 Apparatus
2.1.1 A sample is collected by using a personal sampling pump that can be calibrated to within 5% of the recommended flow rate with the sampling device in line.

2.1.2 OVS-2 tubes, which are specially made 13-mm o.d. glass tubes that are tapered to 6-mm o.d. They are packed with a 140-mg backup section and a 270-mg sampling section of XAD-2 adsorbent. The backup section is retained by two foam plugs and the sampling section is between one foam plug and a 13-mm diameter glass fiber filter. The glass fiber filter is held next to the sampling section by a polytetrafluoroethylene (PTFE) retainer. These tubes are commercially available (i.e., SKC, Supelco).
For problems with accessibility in using figures please contact the SLTC at (801) 233-4900.
Figure 1. OVS-2 Sampling Device

2.2 Reagents

No sampling reagents are required.

2.3 Sampling technique
2.3.1 Attach the small end of the OVS-2 sampling tube to the sampling pump with flexible plastic tubing such that the large front section of the sampling tube is exposed directly to the atmosphere. Do not place any tubing in front of the sampler.

2.3.2 Attach the sampler vertically (large end down) in the employee's breathing zone in such a manner that it does not impede work performance.

2.3.3 After sampling for the appropriate time, remove the sampling device and seal the tube with plastic end caps.

2.3.4 Wrap each sample end-to-end with an OSHA seal (Form 21).

2.3.5 Record the air volume for each sample and list any possible interferences. 

2.3.6 Submit at least one blank with each set of samples. Handle the blank in the same manner as the other samples, except that no air is drawn through it. 

2.3.7 Submit any bulk samples for analysis in a separate container. Do not ship bulk samples with the air samples. 
2.4 Desorption efficiency
 
A 13-mm glass fiber filter and a amount of XAD-2 adsorbent equal to the sampling section (270 mg) of an OVS-2 tube were placed in each of eighteen 4-mL vials. They were divided into three groups of six vials. These groups were liquid spiked respectively with 22, 12 and 2 L of 2.65 mg/mL solution of cypermethrin in toluene by spiking the glass fiber filter. These amounts represent 1.0, 0.5, and 0.l the target concentration. They were then sealed with PTFE-lined septa and allowed to equilibrate overnight in a drawer at room temperature. The vials, along with a blank vial, were desorbed with 3.0 mL of the desorbing solution, and analyzed as in Section 3. The average desorption efficiency was  97.03%. The results are listed in Table 2.4. 
Table 2.4
Desorption Efficiency

Sample # Amount 
Spiked, g
Amount
 Found, g
%
Recovered

D1
D2
D3
D4
D5
D6
60.95
60.95
60.95
60.95
60.95
60.95
58.44
60.72
60.99
56.97
59.37
61.05
95.88
99.62
100.06
93.47
97.47
100.16
Average of 1 TC = 97.70%
D7
D8
D9
D10
D11
D12
31.8
31.8
31.8
31.8
31.8
31.8
32.97
30.78
29.43
30.57
31.56
30.15
103.67
96.79
92.54
96.13
99.24
94.81
Average of 0.5 TC = 97.19%
D13
D14
D15
D16
D17
D18
5.3
5.3
5.3
5.3
5.3
5.3
5.16
5.58
4.98
4.95
5.16
4.77
97.35
105.28
93.96
93.39
97.35
90.00
Average of 0.1 TC = 96.22%
2.5 Retention efficiency

Six OVS-2 tubes were each liquid Spiked with 22 L (l TC) of 2.65 mg/mL solution of cypermethrin in toluene by spiking the glass fiber filter. These were allowed to equilibrate overnight In a drawer at room temperature and then 60 L of humid air (~80% relative humidity) were drawn through each tube at 1.0 L/min. The tubes, along with a blank tube, were desorbed with 3.0 mL of desorbing solution, and analyzed as in Section 3. No analyte was observed in backup sections. The results are listed in Table 2.5.
Table 2.5
Retention Efficiency

Days
 Stored
Amount
 Spiked, g
Amount
 Found, g

Recovered

R1
R2
R3
R4
R5
R6
60.95
60.95
60.95
60.95
60.95
60.95
58.23
56.70
58.95
60.30
57.54
57.54
95.53
93.02
96.71
98.93
94.40
94.40
Average = 95.54%

2.6 Sample storage
 
Twelve OVS-2 tubes were each liquid spiked with 22 L (1 TC) of a 2.65 mg/mL solution in toluene by spiking the glass fiber filter. These tubes were allowed to equilibrate overnight in a drawer at room temperature and then 60 L of humid air (80% relative humidity) were drawn through each tube at 1.0 L/min. The twelve tubes were divided into two groups of six tubes each. The first group was stored in a drawer at ambient temperature, the second group was stored in a freezer (-5C). After fifteen days they were extracted and analyzed as in Section 3. No analyte was observed in backup sections. The results are given in Tables 2.6.1, and 2.6.2. 
Table 2.6.1
Ambient Storage

Days
  Stored
Amount
  Spiked, g
Amount
  Found, g

Recovered

15
15
15
15
15
15
60.95
60.95
60.95
60.95
60.95
60.95
49.92
50.25
47.04
42.12
54.36
46.50
81.90
82.24
77.17
69.10
89.18
76.29
Average = 78.31%

Table 2.6.2
Freezer Storage

Days
  Stored
Amount
  Spiked, g
Amount
  Found, g

Recovered

15
15
15
15
15
15
60.95
60.95
60.95
60.95
60.95
60.95
54.51
53.85
60.51
54.81
57.15
60.84
89.43
88.35
99.27
89.92
93.76
99.81
Average = 93.42%

2.7 Recommended air volume and sampling rate
2.7.1 The recommended air volume is 60 L.

2.7.2 The recommended flow rate is 1.0 L/min.
2.8 Interferences (sampling)

It is not known if any compounds will interfere with the collection of cypermethrin. Any suspected interferences should be reported to the laboratory with submitted samples.

2.9 Safety precautions (sampling)
2.9.1 Attach the sampling equipment in such a manner that it will not interfere with work performance or employee safety.

2.9.2 Follow all safety practices that apply to the work area being sampled.
3. Analytical Procedure
3.1 Apparatus
3.1.1 A GC equipped with an ECD. A Hewlett-Packard 5890A GC (capillary) equipped with both an ECD and a Hewlett-Packard 7673A Autosampler was used in this evaluation.

3.1.2 A GC column capable of separating cypermethrin from any interferences. A 45 m x 0.32 mm i.d. (0.25 um film) SE-30 capillary column was used in this evaluation.

3.1.3 An electronic integrator or some other suitable means to measure detector response. A Waters 860 Networking Computer System was used in this evaluation.

3.1.4 Volumetric flasks, pipets, and syringes for preparing standards, making dilutions and performing injections.

3.1.5 Vials, 2-mL, and 4-mL, with PTFE-lined caps.

3.1.6 Mechanical shaker.
3.2 Reagents
3.2.1 Cypermethrin. A 99% pure standard from EPA was used in this evaluation.

3.2.2 Toluene. The toluene used in this evaluation was purchased from Burdick and Jackson.

3.2.3 p-Chlorobiphenyl. The p-chlorobiphenyl was purchased from ICN.

3.2.4 Desorbing solution. If an internal standard (ISTD) is used, the desorbing solution is prepared by adding 8 L of p-chlorobiphenyl to 100 mL of toluene. Otherwise, toluene can be used.
3.3 Standard preparation
Prepare stock standards by adding desorbing solution to preweighed amounts of cypermethrin. Prepare working range standards by diluting stock solutions with desorbing solution. Store stock and dilute standards in a freezer.
3.4 Sample preparation
3.4.1 Transfer the 13-mm glass fiber filter and the 270-mg sampling section of the tube to a 4-mL vial. Place the first foam plug and the 140-mg backup section in a separate vial. A small glass funnel can be used to facilitate the transfer of the adsorbent. Discard the rear foam plug. Do not discard the glass sampling tube; it can be reused after it has been cleaned by surfactant or solvent washing.

3.4.2 Add 3.0 mL of desorbIng solution to each vial and seal with a PTFE-lined cap.

3.4.3 Shake the vials on a mechanical shaker for half an hour.

3.4.4 If necessary, transfer aliquots of the samples to the appropriate GC vials. In this evaluation, the samples were transferred to 2-mL glass vials, sealed with PTFE-lined septa and loaded on the automatic sampler.
3.5 Analysis
3.5.1 Instrument conditions

Column:
Injector temperature:
Detector temperature:
Column temperature:
Head pressure:
FPD conditions:
hydrogen flow rate:
Injection volume:
Split ratio:
Retention time:
SE-30, 45 m 0.32 mm i.d., 0.25 m film
25C
300C
230C
12 psi

2 mL/min
1 L
11:1
4 Distinctive peaks of cypermethrin ( Rt. window 9.9 - 10.4)

3.5.2 Chromatogram

For problems with accessibility in using figures please contact the SLTC at (801) 233-4900.
Figure 2. Chromatogram of cypermethrin.


3.5.3 Measure detector response using a suitable method such as electronic integration.
3.6 Interferences (analytical)
3.6.1 Any collected compound which produces an ECD response and has a similar retention time as cypermethrin is a potential interference.

3.6.2 GC conditions may generally be varied to circumvent interferences.

3.6.3 Retention time on a single column is not proof of chemical identity. Analysis by an alternate GC column, high performance liquid chromatography (HPLC) and confirmation by mass spectrometry are additional means of identification.
3.7 Calculations
3.7.1 A calibration curve may be constructed by plotting concentration of analyte per mL versus response of standard concentration (ug/mL) of cypermethrin. Cypermethrin has 8 possible isomers, standard used have 4 distinctive peaks. Therefore peak summation is advised for calculation. Bracket the samples with prepared analytical standards over a range of concentrations.

3.7.2 Determine the pg/mL of cypermethrin in both sections of each sample and blank from the calibration curve. If cypermethrin is found on the backup section, It is added to the amount found on the front section. Blank corrctions should be performed before adding the results together.

3.7.3 Determine the air concentration by using the following formula:

mg/m3 = (µg/mL in sample) × (extraction volume, mL)
(air volume, L) × (extraction efficiency, decimal)

ppm =  (mg/m2)(24.46)

229.3

where 24.46 = molar volume (liters) at 101.3 kPa (760 mmHg) and 25C416.3 = molecular weight of cypermethrin 
3.8 Safety precautions (analytical)
3.8.1 Avoid skin contact and air exposure to cypermethrin.

3.8.2 Avoid skin contact with all solvents.

3.8.3 Wear safety glasses in laboratory.
4. Recommendation for Further Study

This method should be fully validated.

5. References
5.1 Burright, D.; Methods #70s "PYRETHRUM"; OSHA Analytical Laboratory, published, 1988.

5.2. "OCCUPATIONAL DISEASE, A Guide to their Recognition"; U.S. Department of Health, Education, and Welfare; Public Health Service, Public Health Service Publication No. 1097, U.S. Government Printing Office: Washington, D.C., 1964; p 245.

5.3 Material safety data sheet, OCCUPATIONAL HEALTH SERVICES.

5.4 "Farm Chemicals Handbook"; Meister Publishing Co.: Willoughby, OH, 1990; PP C99-100.

5.5 Windholz, H., Budavari, S., Blumetti, RF., and Otterbeint Lr., The Merck Index, 11th ed., Merck & CO., Inc., Rahway, N.J., 1983; p 434.