HG 2979-1987 Analytical method for the content of chlorpyrifos technical
Some standard content:
National Standard of the People's Republic of China
Analytical method of content for thlocyelamhydrogen oxalate technical
This standard is applicable to the determination of thlocyelamhydrogen oxalate content. Active ingredient, N,N-methyl-1,2,3. trisulfide cyclohexane-5-amine oxalate. Structural formula:
Molecular formula: C,H.,NO,S,
Molecular weight: 271.38 (International atomic weight in J983) Method summary
EDC 632. 95
GB 8198--87
First, neutralize the thlocyelamhydrogen oxalate with nitrogen water and extract it with n-hexane. Then N, N-dimethyl-1,2,3-trithiocyclohexane-5-amine was separated from the sample by thin layer chromatography, and the absorbance was measured at 265 nm by UV spectrophotometry. 2 Apparatus
Folding cylinder,
Glass plate: 20cm×20cm
UV spectrophotometer
UV lamp: 254nm;
Volume flask, 25ml,
Pipette: 10ml, 5ml;
Graduated pipette: 1ml:
Lifting funnel-: 60 ml;
Sand core filter: C3~G5.
Silica gel·GF.: for thin layer chromatography;
n-hexane: analytical grade;www.bzxz.net
2. Ether (HG3-100276): analytical grade; anhydrous Z. alcohol (GB678-78): analytical grade; methanol (GB683-79): analytical grade;
Ammonia ice B631
7): pure, 1+1 hydrogen water soluble;
General test paper: pH 1~14:
Cyclocyclamide standard: content 99.6%.
The Ministry of Chemical Industry of the People's Republic of China approved Pgr
1988-05-01 on April 17.
4 Determination steps
GE8198
4.1 Preparation of chromatography plates
The plates were coated by flat-laying method (about 10 g of gelatin-GFs per plate, plate thickness 0.5 mm), placed horizontally to air dry, and then dried in an oven at 110-5°C for about 2 hours, and placed in a desiccator for storage. 4.2 Preparation of calibration curve
Weigh 0.125g (accurate to 0.0002g) of insecticide standard and place it in a 25ml container. Dissolve it in distilled water and dilute to the mark. Pipet 10ml accurately and place it in a 60ml separatory funnel. Add 1+1 hydrogenated water to neutralize it to pH 8 (check with standard test paper). Extract twice with n-hexane, adding 5ml each time. Combine the n-hexane solutions and use a 1ml graduated pipette to accurately pipette D.2, (.40.6, 0.8, 1.1ml of the above n-hexane solutions into a volumetric flask respectively. Add anhydrous ethanol to the mark and shake well. Put the above concentration standards into a 1cm quartz colorimetric container in turn and shake with anhydrous ethanol. Alcohol is used as a reference. Select the wavelength of 265mm as the quantitative absorption peak in the UV spectrophotometer 1, measure the absorbance D, use it as the ordinate, and the standard solution concentration as the abscissa to draw a graph, and get a straight line through the origin (as shown in Figure 1).
: Tug/25ml
Figure 1 Weight curve
4.3 Thin separation
Weigh about 50mg (accurate to 0.2mg) of the original drug containing the active ingredient of the insecticide ring in a tuml separation funnel: dissolve it completely in distilled water, add 1+] nitrogen water to neutralize it to about pH8 (check with a wide range of test paper), extract it twice with n-hexane, accurately add 5m n-hexane each time, combine the total n-hexane solution, and use 1m Use a graduated pipette to accurately draw 0.6 ml of n-hexane solution, and place the sample in a thin straight line on a tri-activated chromatography plate at 3 cm from the bottom and 1.5 cm on both sides. Scrape off 5 mm wide silica gel on both sides of the thin layer plate to prevent the developer from spreading along the edge. Scrape off 1 ton wide silica gel parallel to the top edge at 3 cm from the top edge of the thin layer plate. This band is used as the upper limit of the developer development. After the sample spotting solvent evaporates, place the plate upright in a chromatography cylinder filled with the developer (ether and methanol, the mixed solvent volume ratio is 95+5) vapor. The depth of the plate immersed in the solvent is ?-10 mm. When the developer rises to the pre-marked limit, take it out of the cylinder and put it in a ventilated container. Let the solvent on plate E evaporate, then place the plate under ultraviolet light for color development, draw out the band containing NN-dibenzyl 1,2,3, trisulfide cyclohexane-5-amine at around R=0.37 on the plate, then transfer all the bands into the sand core, and elute twice with 21ml of anhydrous ethanol, 7ml each time, collect the eluate in a 25ml volumetric flask, and make up to volume for use. This ethanol eluate can be used for determination. Perform the above operation on the unspotted thin layer plate to obtain the blank as the reference.
4.4 Quantification of samples
Put the ethanol eluate after thin layer separation into a 1m quartz colorimetric tank, use the dense white solution as the reference, and measure the concentration in the ultraviolet spectrophotometer! , 2
GB 8198 -87
Select the wavelength of 265nm to measure the absorbance of the sample. 5 Calculation
The percentage of insecticide ring in the sample with the corresponding concentration of absorbance D found on the standard curve (X) is calculated as follows: X
Where, - the mass of insecticide ring corresponding to the absorbance found on the standard curve, mg; - the amount of sample, ..
The parallel relative deviation of this method is within +2.0%. Additional remarks:
This standard is under the technical supervision of Shenyang Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Municipal Pesticide Research Institute. The main drafters of this standard are Ye Wenbing and Chen Zhongneng.
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