ICS 65.100.20  
G 25  
GB 
 
National Standards of the People’s Republic of China  
 
GB XXXX - XXXX  
 
 
 
 
 
Pendimethalin Technical  
 
 
 
 
(Draft for Approval)  
(Draft completion date: December 2006)  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Issue Date: 200X – XX -XX               Implementati on 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 s tandard 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 Committee  (CSBTC/TC13 3). 
 
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 Longdeng 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 Committee.  
    
 
Pend imethalin Technical  
 
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 (by 2001 the international atomic relative mass)  
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 
transportation methods for pendimethalin te chnical.  
 
This standard applies to pendimethalin and pendimethalin technical composed by 
production impurities.  
  
2 Normative References  
 
The provisions in the following documents 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 lat est 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 1604  Acceptance regulations for commercial pesticides  
GB/T 1605 -2001  Sampling method for commercial pesticide s 
GB 3796  General rule for packing of pesticides     
GB/T 19138  Testing method of material insoluble in acetone for pesticides  
 
3 Requirements  
 
3.1 Composition and Appearance:  
 
This product should be a brown -yellow to orange crystal powder without any 
visible foreig n ingredients or added modifier.  
 
3.2 Pendimethalin technical should meet the requirements set out in Table 1.  
 
Table 1 – Control Items and Guidelines  
for Pendimethalin Technical  
Item Guideline  
Pendimethalin mass fraction /%       95.0 
Water /%                                           0.5 
pH range  4.0 to 8.0  
Acetone insoluble /% a)                      0.5 
a) Under normal production conditions, insoluble -acetone should be tested at 
least every 3 months.  
 
4 Test Method  
 
4.1 Sampling  
 
Sampling should be carried  out in line with the Commodity Pesticide 
Technical 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 100g.  
 
4.2 Iden tification Test  
 
4.2.1 Liquid chromatography : this identification test can be carried out at the 
same time as the pendimethalin content test. Under the same chromatographic 
operation conditions, the relative difference between the retention time of 
certain chrom atographic 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%.  
 
4.2.2 Gas chromatography : this identification test can be carried out at the same 
time as the pendimet halin 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 chromatographic peak of pendimethalin in the s tandard 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 ste el column with ODS (C18) as filler and an 
ultraviolet detector. Conduct the reversed phase chromatographic isolation and 
measurement of pendimethalin in the sample.  
 
4.3.1.2  Reagent and Solution  
 
Acetonitrile: chromatographic pure;  
Water: secondary distilled wate r;  
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 about 0.45  m;  
Quantitative sampling tube: 5  l;  
Micro dosing unit: 50  l;  
Ultrasonic cl eaner.  
 
4.3.1.4  Liquid chromatography operating condition  
 
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 n m;  
Sampling volume: 5  l;  
Retention time: 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 th e best result. A typical high performance liquid 
chromatogram of pendimethalin technical is shown in Figure 1.     
   
  
 
1 – Pendimethalin  
 
Figure 1 - High performance liquid chromatogram  
of pendimethalin technical  
 
4.3.1.5  Test Procedure  
 
4.3.1.5.1  Preparation of standard sol ution  
 
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 50ml 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 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.  
 
4.3.1.5.3  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.  
 
4.3.1.6  Calculation  
 
The mass fraction 1 (%) of pendimethalin in the sample is calculated using 
formula (1):  
  
     
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 pendime thalin, unit expressed in grams (g);  
m2 - mass of the sample, unit expressed in grams (g);  
 – mass fraction of the standard pendimethalin, %;  
 
4.3.1.7  Tolerance  
 
The difference between the results from two parallel tests should not exceed 
1.0%. Take the calcu lated 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 25 0  m as filler and a hydrogen 
flame ionisation detector. Conduct the gas chromatographic isolation and 
measurement of pendimethalin in the sample.  
 
4.3.2.2  Instrument  
 
Gas chromatography: hydrogen flame ionisation detector;  
Chromatographic data processor or chrom atography 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%;  
Dipe ntyl phthalate: without any impurity to interfere 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 
evenly.  
 
4.3.2.4  Gas chromatography opera ting condition  
 
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 substa nce. 
 
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 technical and  internal standard substance is shown in Figure 2.  
   
  
1 - Solvent;  
2 - Pendimethalin;  
3 – Internal standard substance (dipentyl phthalate).  
 
Figure 2  - Gas chromatogram of pendimethalin technical and internal 
standard substance  
 
4.3.2.5  Test Procedure  
 
4.3.2.5.1  Prepara tion 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 bas eline 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 standard 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 (2):     
  
  
 
1 - average ratio between the pendimethalin and internal standard peak areas 
in the standard solution;  
2 - average ratio between the pendimethalin and internal standard peak are as 
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, %;  
 
4.3.2.7  Tolerance  
 
The difference between the results f rom two parallel tests should not exceed 
1.0%. 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  
 
Take a sample acco rding to the requirements stipulated in GB / T 1601. 
Dissolve with a solution of  (acetone: water) = 65:35 and take measurement 
using the pH value test method for pesticides in GB / T 1601.  
 
4.6 Acetone insoluble test  
 
The acetone insoluble test should be carried out as according to GB/T 19138.  
 
4.7 Product inspection and 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 pendim ethalin technical should 
conform to the provisions set out in GB 3796.  
 
5.2 Pendimethalin technical should be packed in plastic barrels or steel barrels 
with plastic lining, without direct contact with the metal. The net content of 
each barrel should be 25kg, 50kg or 200kg.  
 
5.3 Other forms of packaging may be used in accordance with the requirements of 
the customer or contrasting orders, but should in all cases meet the provisions 
set out in GB 3796.  
    
5.4 Pendimethalin technical packs should be stored in well -ventila ted and dry 
warehouses.  
 
5.5 During transportation, strict precautions should be taken against dampness and 
direct sunlight; the product 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.  
 
5.6 Safety : pendimethalin falls into the category mildly toxic. It is toxic when 
swallowed or inhaled and can be infiltrated through the skin. Protective 
goggles, rubber gloves and other necessary protective clothing should be wor n 
when dealing with this product. In case of contact with the skin or eyes it 
should be rinsed immediately with plenty of water; in case it is eaten by 
mistake, the person affected should be sent to hospital immediately for 
emergency treatment.  
 
5.7 Acceptanc e period : the acceptance period for pendimethalin technical is one 
month. Quality acceptance should be completed within one month from 
delivery and each guideline should meet the requirements of this standard.  
 
 
 
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