Cleanert^®PestiCarb/NH₂
Cleanert^®PestiCarb/NH₂Equal amounts of graphitized carbon (PestiCarb) and amino (NH)₂）Filled up. Graphitic carbon has undergone special surface treatment and has strong adsorption capacity for planar molecules, such as chlorophyll and carotenoids in fruits and vegetables; NH₂ Aminopropyl bonded silica gel is used to remove interfering substances such as fatty acids and organic acids; This solid-phase extraction column is widely used in pesticide residue analysis, applied to the detection of various pesticide residues involved in Japan's Positive List System, and also applied to the determination and analysis methods of 500 pesticide and related chemical residues in fruits and vegetables according to GB 23200.8-2016 National Food Safety Standard.

Cleanert^®PestiCarb/PSA
Cleanert^®PestiCarb/PSA is filled with equal amounts of PestiCarb graphitized carbon (upper layer) and PSA (lower layer), separated by a polyethylene sieve plate in the middle. Graphitic carbon has undergone special surface treatment and has strong adsorption capacity for planar molecules, such as chlorophyll and carotenoids in fruits and vegetables; PSA is N-propylethylenediamine bonded silica gel, used to remove fatty acids, organic acids, as well as some polar pigments and sugars and other interfering substances; Compared with NH2, it has both primary and secondary amines, which makes it more effective in removing fatty acids. It is also used for purifying fat rich samples such as animal tissues, milk, and eggs in Japan's Positive List System.

Cleanert^®SAX/PSA
Cleanert^®SAX/PSA is composed of equal amounts of SAX (upper layer) and PSA (lower layer) packed together, separated by a polyethylene sieve plate in the middle. SAX is a quaternary ammonium salt bonded silica gel, and PSA is an N-propylethylenediamine bonded silica gel. Both materials are designed to remove acidic interferences such as fatty acids and organic acids, and are used in the Luke and Luke 11 methods. In GC/MS analysis of pesticides in food, they can significantly reduce matrix effects and improve detection sensitivity.

Usage method of double-layer column purification column

For multi pesticide residue detection, it is very difficult to choose a material that can adsorb all pesticide residues and wash them out. Therefore, a double-layer column uses two sets of materials to work together to remove interfering substances from the matrix without retaining pesticide residue analytes.
As shown in the figure, after the purification column is activated and moistened, the sample is immediately added to the purification column at the moment when the activation solution is about to dry. After the sample is loaded, an appropriate amount of eluent is added, and the eluent is concentrated to near dryness. After re volume filtration, the sample is ready for injection.

【 Solution 】 GC-MS method for determination of 500 pesticide residues in vegetables and fruits

Sample extraction

Weigh 20 g of the sample (accurate to 0.01 g) into an 80 mL centrifuge tube, add 40 mL of acetonitrile, homogenize and extract at 15000r/min for 1 minute using a homogenizer, add 5 g of sodium chloride, and extract again for 1 minute. Place the centrifuge tube into the centrifuge and centrifuge at 3000r/min for 5 minutes. Take 20 mL of the supernatant (equivalent to 10 g of the sample) and wait for purification.

Purification method

Place Cleanert C18 column on Qdaura^®Zhuorui fully automatic solid-phase extraction instrument, transfer all 20 mL of supernatant to the upper sample tube, set the program as follows: activate 10 mL acetonitrile (flow rate 2 mL/min), add sample (flow rate 1 mL/min), wash the column with 15 mL acetonitrile (flow rate 2 mL/min), collect the sample solution and eluent, take out the collected solution and rotate it in a 40 ℃ water bath to concentrate to about 1 mL for later use.

Add approximately 2 cm of anhydrous sodium sulfate to the Cleanert PestiCarb/NH2 composite column and place it in Qdaura ® Zhuorui fully automatic solid-phase extraction instrument, activated with 4 mL acetonitrile/toluene (3:1), transferred the sample concentrate to the upper sample tube for complete loading. Rinse the PestiCarb/NH2 composite column with 25 mL acetonitrile: toluene (3:1) (flow rate of 1mL/min), collect the loading and elution solution, take out the collection solution, and rotate it in a 40 ℃ water bath to concentrate to about 0.5 mL. Add 5 mL n-hexane each time and evaporate it in a 40 ℃ water bath. Perform solvent exchange twice, and finally make the sample liquid volume about 1 mL. Add 40 μ L internal standard solution, mix well, filter through a 0.22 μ m filter, and use it for GC-MS determination.

Note: The above solid-phase extraction process can also be completed in a 6-position large volume solid-phase extraction device.

Chromatographic conditions

Chromatographic column:DA-1701(30 m × 0.25 mm × 0.25 μm)

Temperature program:Maintain at 40 ℃ for 1 minute, then heat up to 130 ℃ using a 30 ℃/min program, then heat up to 250 ℃ at 5 ℃/min, and finally heat up to 300 ℃ at 10 ℃/min for 5 minutes

Carrier gas:HeCurrent Speed:1.2 mL / minInjection port temperature:290 ℃

Injection volume:1μLInjection method:No diversion injectionElectron bombardment source:70eV

Ion source temperature:230 ℃GC-MS interface temperature:280 ℃ SIM monitoring mode

Ordering Guide:

For specific methods, please refer to GB/T 19648-2006 Method for Multiple Residues of 500 Pesticides in Vegetables and Fruits

Application ID: MF10002