ICS 65.100.20  
G 25  
GB 
 
National Standard of the People’s Republic of China  
 
GB XXXX - XXXX  
 
 
 
 
 
Pendimethalin Emulsifiable Concentrates  
 
 
 
 
(Draft for approval)  
(Draft completion date: December 2006)  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Issue Date: 200X – XX -XX               Implementation Date: 200X –XX -XX 
 
 
Issued by the General Administration of Quality Supervision, Inspection and 
Quarantine of the People’s Republic of China and the Standardisation 
Administration of the People’s Republic of China     
 
Foreword  
 
Articles 3 and 5 of this standard are mandatory, while the rest are recommended.  
 
This standard is proposed by the China Petroleum and Chemical Industry Association .  
  
This standard is under the jurisdiction of the National Pesticide Standardisation 
Technical Commi ttee (CSBTC/TC133) . 
 
The organisation in charge of drafting this standard was: Shenyang Chemical Industry 
Research Institute.  
 
The organisations which participated  in the drafting of this standard were: Shandong 
Huayang Technology Co., Ltd and Jiangsu Long deng Chemical Co., Ltd.  
 
The main drafters of this standard were: Zhang Pilong, Hou Chunqing, Zhu Fengxia, 
Feng Xiuzhen and Li Peng.  
 
The interpretation of this standard is entrusted to the secretariat of the National 
Pesticide Standardisation Technical Co mmittee.  
    
 
Pendimethalin Emulsifiable Concentrates  
 
Other names of this product legitimately containing the ingredient p endimethalin , its 
structure and basic physical and chemical parameters are as follows:  
 
ISO common name: Pendimethalin  
CIPAC numerical code: 357  
Chemical name: N-(1 - ethylpropyl) - 2, 6 - nitro -3, 4 - dimethylaniline  
 
   
  
 
Molecular formula: C13H19N3O4 
Relative molecular weight: 281.3 (the international atomic relative mass by 2001)  
Biological activity: weeding  
Melting point: 54  to 58   
Vapour pressure (25 ): 4.0 × 10-3Pa 
Solubility (26 , g/l): water 3.0 × 10-4 (20 ), acetone 700, corn oil 148, isopropanol 
77, xylene 628, heptane 138, soluble in benzene, toluene, chloroform and 
dichloromethane, slightly soluble in petroleum ether and petrol  
Stability: stable in 5  to 130 , DT 50 < 21d in water, stable in acid and alkali, DT 50 
= 30d to 90d in soil, slowly decomposed under light.  
 
1 Scope  
 
This standard sets the requirements, test methods, marking, labelling, packaging and 
transportat ion methods for pendimethalin emulsifiable concentrates.  
 
This standard applies to pendimethalin emulsifiable concentrates and concentrates 
made from pendimethalin in proper emulsifier  solution.  
 
2 Normative References  
 
The provisions in the following docum ents become provisions of this standard after 
being referenced. For dated reference documents, all later amendments (excluding 
corrigenda) and versions do not apply to this standard; however, the parties to the 
agreement are encouraged to study whether the  latest versions of these documents 
apply. For undated reference documents, the latest versions apply to this standard.  
 
GB/T 1600  Testing method of water in pesticides  
GB/T 1601  Testing method for the pH value of pesticides  
GB/T 1603  Determination of the emulsion stability of pesticides  
GB/T 1604  Acceptance regulations for commercial pesticides  
GB/T 1605 -2001  Sampling method for commercial pesticides     
GB/T 4472  General test rule for determination of density and relative density 
of chemical products  
GB 4838  Packaging for emulsifiable concentrates of pesticides  
GB/T 19136  Testing method for the storage stability of pesticides at elevated 
temperature  
GB/T 19137  Testing method for the storage stability of pesticides at low 
temperature  
3 Requirements  
 
3.1 Composition a nd Appearance:  
 
This product should be made with pendimethalin technical and emulsifier  
dissolved in appropriate solvent, and should be a stable homogeneous liquid.  
 
3.2 Pendimethalin emulsifiable concentrates should meet the requirements set out 
in Table 1.  
 
Table 1 – Control Items and Guidelines  
for Pendimethalin Emulsifiable Concentrates  
Guideline  
Item 
33% 330g/l  
33.0 +1.7
-1.7 33.5 +2.0
-2.0 Pendimethalin mass fraction /% a) 
or mass density (20 ) / g/L  - 330 +2.0
-2.0 
Water /%                         0.5 
pH range  5.0 to 8.0  
Emulsion stability (diluted 200 times)  pass 
Low temperature stability b) pass 
Elevated temperature storage stability b) pass 
a) If the mass is disputable, it should be arbitrated by the mass fraction.  
b) Under normal production condi tions, the low temperature stability and 
elevated temperature storage stability tests should be conducted at least 
every 3 months.  
 
 
4 Test Method  
 
4.1 Sampling  
 
Sampling should be carried out in line with the Liquid Preparation Sampling 
Method set out in GB/T  1605 -2001.  A random sampling method should be 
used to determine which package shall be used as the sample, and the final 
sample quantity should not be less than 200ml.  
 
4.2 Identification Test  
    
4.2.1 Liquid chromatography : this identification test can be carried o ut at the 
same time as the pendimethalin content test. Under the same chromatographic 
operating conditions, the relative difference between the retention time of 
certain chromatographic peaks in the sample solution and the retention time of 
the chromatogra phic peak of pendimethalin in the standard solution should be 
less than 1.5%.  
 
4.2.2 Gas chromatography : this identification test can be carried out at the same 
time as the pendimethalin content test. Under the same chromatographic 
operating conditions, the rela tive difference between the retention time of 
certain chromatographic peaks in the sample solution and the retention time of 
the chromatographic peak of pendimethalin in the standard solution should be 
less than 1.5%.  
 
4.3 Pendimethalin mass fraction test  
 
4.3.1 Liquid chromatography (Arbitration method)  
 
4.3.1.1  Summary of Method  
 
Dissolve the sample in acetonitrile solution. Apply acetonitrile + water as the 
mobile phase; use a stainless steel column with ODS (C18) as filler and an 
ultraviolet detector. Conduct the reverse d phase chromatographic isolation and 
measurement of pendimethalin in the sample.  
 
4.3.1.2  Reagent and Solution  
 
Acetonitrile: chromatographic pure;  
Water: secondary distilled water;  
Standard pendimethalin: known content  99.0%.  
 
4.3.1.3  Instruments  
 
Liquid chromatography: variable ultraviolet wavelength detector and 
quantitative sampling valve;  
Chromatographic data processor or chromatography workstation;  
Chromatographic column: 200 mm × 4.6mm (i.d.) stainless steel column with 
Hypersil ODS 5  m filler (or other reversed phase columns with the same 
column effect);  
Filter: membrane pore diameter around 0.45  m;  
Quantitative sampling tube: 5  l;  
Micro dosing unit: 50  l;  
Ultrasonic cleaner.  
 
4.3.1.4  Liquid chromatography operating c onditions  
 
Mobile phase:  (acetonitrile: water) = 60:40;  
Mobile phase flow volume: 1.0 ml/min;  
Column temperature: room temperature (the temperature fluctuation should 
not exceed 2 );     
Detecting wavelength: 240 nm;  
Sampling volume: 5  l;  
Retention t ime: 13.5 min for pendimethalin.  
 
The above are typical operating parameters. The given operating parameters 
may be adjusted appropriately according to the characteristics of different 
instruments, so as to obtain the best result. A typical high performanc e liquid 
chromatogram of pendimethalin emulsifiable concentrates is shown in Figure 
1. 
   
  
 
1 – Pendimethalin  
 
Figure 1 - High performance liquid chromatogram  
of pendimethalin emulsifiable concentrates  
 
4.3.1.5       Test Procedure  
 
4.3.1.5.1  Preparation of standard soluti on  
 
Take 0.1g standard pendimethalin (accurate to 0.0002 g) and place in a 50ml 
measuring flask then dissolve with acetonitrile, diluting the solution to the 
scale, and shake evenly. Using a pipette, take 5ml of the above solution and 
place in another 50m l measuring flask. Dilute to the scale by mobile phase and 
shake evenly.  
 
4.3.1.5.2  Preparation of sample solution  
 
Take a 0.1g sample  of pendimethalin (accurate to 0.0002 g) and place in a 
50ml measuring flask. Dissolve it with acetonitrile, dilute the solution to  scale 
and shake evenly. Using a pipette, take 5ml of the above solution and place in 
another 50ml measuring flask. Dilute to scale by mobile phase and shake 
evenly.  
 
4.3.1.6  Test 
 
Under the above operating conditions and after the baseline of the instrument 
is st abilised, continuously syringe several doses of the standard solution, 
calculating the repetition of the corresponding response value of each dose 
until the pendimethalin peak area’s variation of two adjacent doses is less than    
1.2% and then measure in seq uence the standard solution, sample solution, 
sample solution and standard solution.  
 
4.3.1.7  Calculation  
 
The mass fraction  1 (%) of pendimethalin in the sample is calculated using 
formula (1):  
  
  
 
The mass density  1 (g/L) of pendimethalin in the sample is ca lculated using 
formula (2):  
  
  
In the formula:  
A1 – average peak area of pendimethalin in the standard solution;  
A2 – average peak area of pendimethalin in the sample solution,  
m1 – mass of the standard pendimethalin, unit expressed in grams (g);  
m2 – mass of the sample, unit expressed in  grams (g);  
 – mass fraction of the standard pendimethalin, %;  
  – density of the sample at 20 , unit expressed in g/ml, tested according to 
GB/T 4472.  
 
4.3.1.8  Tolerance  
 
The difference between the results of two parallel tests should not exceed 
0.8%. Take the calculated average as the test result.  
 
4.3.2 Gas chromatography  
  
4.3.2.1  Summary of Method  
 
Dissolve the sample in chloroform solution. Apply dipentyl phthalate as the 
internal standard; use a glass chromatographic column with 5% OV -
101/Chromosorb W AW DMCS, 180  m to 250  m as filler and a hydrogen 
flame ionisation detector. Conduct the gas chromatographic isolation and 
measure the pendimethalin content in the sample.  
 
4.3.2.2  Instruments  
 
Gas chromatography: hydrogen flame ionisation detector;  
Chromatographic data pro cessor or chromatography workstation;  
Chromatographic column: 1m × 3.2mm (i.d.) glass column with 5% OV -
101/Chromosorb W AW DMCS, 180  m to 250  m filler;  
Micro dosing unit: 10  L.  
 
4.3.2.3  Reagent and Solution  
    
Chloroform;  
Pendimethalin sample: known content   99.0%;  
Dipentyl phthalate: without any impurities that may interfere with the analysis;  
Internal standard solution: take 5g dipentyl phthalate and place in a 1,000ml 
measuring flask. Dissolve in chloroform, dilute the solution to scale and shake 
evenl y. 
 
4.3.2.4  Gas chromatography operating conditions  
 
Temperature ( ): column temperature 175, gas chamber 200, detector 
chamber 200;  
Gas flow (ml / min): carrier gas (N2) 40, hydrogen 35, air 350;  
Sampling volume ( l): 0.5;  
Retention time (min): about 9.4 for pendimethalin, about 14.0 for the internal 
standard substance.  
 
The above are typical operating parameters. The given operating parameters 
can be adjusted appropriately according to characteristics of different 
instruments, so as to obtain the best result.  A typical gas chromatogram of 
pendimethalin emulsifiable concentrates and internal standard substance is 
shown in Figure 2.  
   
  
1 - Solvent;  
2 - Pendimethalin;  
3 - Dipentyl phthalate.  
 
Figure 2  - Gas chromatogram of pendimethalin emulsifiable concentr ates 
and internal standard substance  
 
4.3.2.5  Test Procedure  
 
4.3.2.5.1  Preparation of standard solution  
 
Take 0.1g standard pendimethalin (accurate to 0.0002 g) and place in a 10ml 
bottle with a plug. Using a pipette, add 10ml internal standard solution and 
shake evenly, so as to dissolve it.  
 
4.3.2.5.2  Preparation of sample solution     
 
Take a 0.1g sample pendimethalin (accurate to 0.0002 g) and place in a 10ml 
bottle with a plug. Using the same pipette as indicated in 4.3.2.5.1, add 10ml 
internal standard solution and shake evenly.  
 
4.3.2.5.3  Test 
 
Under the above operating conditions and after the baseline of the instrument 
is stabilised, continuously syringe several doses of the standard solution, 
calculating the repetition of the peak area ratio of the pendimethalin and the 
internal standa rd substance; when the variation of the peak area ratio of the 
pendimethalin and the internal standard substance of two adjacent doses 
becomes less than 1.2%, measure in sequence the standard solution, sample 
solution, sample solution and standard solution . 
 
4.3.2.6  Calculation  
 
The mass fraction  1 (%) of pendimethalin in the sample is calculated using 
formula (3):  
  
  
 
The mass density  1 (g/l) of pendimethalin in the sample is calculated using 
formula (4):  
  
  
1 - average ratio between the pendimethalin and in ternal standard peak areas 
in the standard solution;  
2 - average ratio between the pendimethalin and internal standard peak areas 
in the sample solution;  
m1 – mass of the standard pendimethalin, unit expressed in grams (g);  
m2 – mass of the sample, uni t expressed in grams (g);  
  - mass fraction of the standard pendimethalin, %;  
  - density of the sample at 20 ,unit expressed in g/ml, tested according to 
GB/T 4472.  
 
4.3.2.7  Tolerance  
 
The difference between the results of two parallel tests should not exceed  
0.8%. Take the calculated average as the test result.  
 
4.4 Water content test  
 
The water content test should be carried out according to the Karl Fisher 
method as set out in GB/T 1600.  
 
4.5 pH value test  
 
The pH value test should be carried out according to GB/T 1601.     
 
4.6 Emulsion stability test  
 
Dilute the sample 200 times its quantity with standard hard water and carry 
out the test according to GB/T 1603. The test meets the requirements if there 
is no floating or depositing oil or sedimentation found.  
 
4.7 Low temperat ure test  
 
The low temperature test should be carried out according to GB/T 19137. The 
test meets the requirements if the size of any separated solid or liquid does not 
exceed 0.3ml.  
 
4.8 Storage stability test at elevated temperature  
 
The test should be carrie d out according to GB/T 19136. Complete the 
pendimethalin mass fraction and emulsifiable  concentrate stability tests within 
24 hours after storing at the elevated temperature and the result should meet 
the requirements set out in 3.2.  
 
4.9 Product inspection a nd acceptance  
 
Product inspection and acceptance should conform to the provisions set out in 
GB/T 1604. Limiting values should be processed using the rounding off 
comparison method.  
 
5 Marking, labelling, packaging and transportation  
 
5.1 The marking, labelling  and packaging of pendimethalin emulsifiable 
concentrates should conform to the provisions set out in GB 4838.  
 
5.2 Pendimethalin emulsifiable concentrates can be packed either in brown glass 
bottles or PET bottles with plugs and caps. The net content of each bottle 
should be 100g, 200g, 500g etc.; calcium -plastic boxes should be used for the 
outer packaging and the net content weight for each box should not exceed 
20kg.  
 
5.3 Other forms of packaging may be used in accordance with the requirements of 
the customer o r contrasting orders, but should in all cases meet the provisions 
set out in GB 4838. Pendimethalin emulsifiable concentrate packs should be 
stored in well -ventilated and dry warehouses.  
 
5.4 During the transportation of pendimethalin emulsifiable concentrates , strict 
precautions should be taken against dampness and direct sunlight; they should 
not be placed together with food, seeds or feedstuff, and contact with the skin 
and eyes and inhaling into the mouth and nose should be avoided.  
 
5.5 Safety : pendimethalin f alls into the category mildly toxic. Protective gloves 
should be worn when dealing with this product. In case of contact with the 
skin, it should be washed out with soap and water immediately; in case of    
inhaling, the person affected should be moved to a pl ace with plenty of fresh 
air; in case of spattering into the eye, it should be rinsed with plenty of water; 
in case of poisoning, the person affected should be sent to hospital 
immediately for emergency treatment.  
 
5.6 Warranty : under the specified storage co nditions, the warranty of 
pendimethalin emulsifiable concentrates should be two years from the date of 
production.  
  
 
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