Pesticide residue chromatographic analyzer

With the improvement of people's living standards and the continuous attention to their own health level. Food safety has become a highly valued issue for everyone. The issue of pesticide residues is receiving increasing attention from people. Due to the need to ensure freshness in the use of vegetables and fruits, especially leafy vegetables, the time from harvesting to market to public consumption is relatively short. Developing fast, reliable, sensitive, and practical pesticide residue analysis technology is the foundation for controlling pesticide residues and ensuring food safety.
Governments around the world have established strict pesticide residue limit standards. The European Union has proposed 124 pesticide residues for fruits, and the United States has proposed over 300 pesticide residues. The purpose is to control pesticide abuse and safeguard the interests of the people. Therefore, developing a rapid method for detecting pesticide residues is of great significance for ensuring food safety.
Tengzhou Tenghai Analytical Instrument Co., Ltd. has launched the GC-6890 gas chromatograph, which provides rapid and accurate analysis of organophosphorus, organochlorine, and pyrethroid pesticide residues in food.
1、 Analysis method of GC-6890 gas chromatograph for pyrethroid pesticides:
1.1 Main reagents: Acetone (chromatographic grade), Acetonitrile (pesticide residue grade), n-Hexane (pesticide residue grade), Anhydrous Sodium Sulfate (high-purity).
1.2 Gas chromatography detection conditions: gasification chamber temperature of 220 ℃, ECD detector, temperature of 300 ℃. Program heating: 200 ℃, hold for 1 minute; Raise the temperature to 230 ℃ at a rate of 30 ℃/min and keep it for 20 minutes; Raise the temperature to 270 ℃ at a rate of 20 ℃/min and keep it for 5 minutes
1.3 Sample Processing and Purification:
1.3.1 Sample processing: Cut the vegetable sample into pieces and crush them in a food grinder Accurately weigh 25.00g of the sample and pour it into a high-speed tissue grinder. Add 50.00ml of acetonitrile and homogenize at high speed for 3 minutes. Pour it into a 100ml stoppered graduated cylinder containing 5-7g of sodium chloride, filter, collect the filtrate, cover with a lid, shake for 0.5-1 minute, and let it stand at room temperature for 10-15 minutes until the acetonitrile and water phases separate
1.3.2 Sample Purification: Accurately take 10.0 ml of organic phase solution and place it in a 100 ml beaker. Concentrate it to near dryness on a nitrogen blower (heat it to 80 ℃ in a water bath), and add 2 ml of n-hexane Alkylate the Florisil solid-phase extraction column with 5ml of 10% acetone n-hexane, add the dissolved sample in the beaker to the conditioned Florisil column, and collect the eluent in a 15ml centrifuge tube. Wash the beaker twice with 5ml of 10% acetone n-hexane and also add it to the column for elution. Concentrate the collected eluent on a nitrogen blower to below 5ml (water bath temperature 55 ℃), then elute on an anhydrous sodium sulfate chromatography column (wash the column with 10ml of 10% acetone n-hexane), dissolve the n-hexane to 5.0ml, and analyze by GC-ECD
2、 GC-6890 typegas chromatographAnalysis methods for organochlorine pesticides:
2.1 Reagents and chromatographic conditions: Organic chlorine is detected using an ECD detector, and the chromatographic columns are 0.3% OV-17 and 2.7% OV-210/chromosorbWHP columns; The temperature of the injection port and detector is 240 ℃; The column temperature is 190 ℃; The nitrogen flow rate is 50 ml/min; Using the external standard method, quantitative analysis is conducted based on peak height. Reagents: Acetone, petroleum ether (30-60 ℃), sulfuric acid, anhydrous sodium sulfate, dichloromethane, activated carbon Organic phosphorus is detected using an FPD detector, and the chromatographic column is a 5% SE-30/chromosorbWAW column; The temperature of the injection port and detector is 240 ℃; The column temperature is 200 ℃; The nitrogen flow rate is 50ml/min; The hydrogen flow rate is 50ml/min; The air flow rate is 50ml/min; The injection volume is 2ul; the mixed concentration is 10ug/ml for dichlorvos, organophosphate, dimethoate, parathion, and malathion. Using external standard method for quantitative analysis based on peak height
2.2 Sample Preparation All samples were obtained directly from the vegetable market without cleaning, and were directly crushed for pre-treatment Pre treatment for organic chlorine determination Take 5g of crushed sample, soak it in acetone for extraction, then extract it with petroleum ether, sulfonate it with sulfuric acid until colorless, wash it with anhydrous sodium sulfate solution, filter it with anhydrous sodium sulfate, and dilute it to 10ml. Pre treatment for organic phosphorus determination Mix 5g of crushed sample with 50g of anhydrous sodium sulfate and 0.3-0.5g of activated carbon, shake, and extract with dichloromethane. After filtration and evaporation, the extract is diluted to 10ml. All organic chlorine and organic phosphorus treatment solutions are colorless and transparent.
3、 GC-6890 gas chromatograph analysis method for organophosphorus pesticides:
3.1 Instruments and main chemical reagents: equipped with FPD detector, phosphorus filter (525cm). SPME handle with 85um polyacrylate fiber head Five types of organic phosphorus pesticides were provided by the National Standard Material Center, with concentrations of 2.0mg/ml for dichlorvos, 1.0mg/ml for dichlorvos, 1.1mg/ml for dimethoate, 1.04mg/ml for methyl parathion, and 1.0mg/ml for parathion
3.2 Chromatographic conditions: The capillary column is CBP10-M25-025 (Shimadzu Corporation) The column temperature starts at 80 ℃ and is maintained for 1 minute. Then, it rises to 230 ℃ at a rate of 10 ℃ per minute and is maintained for 9 minutes. The sample is divided into two streams with a split ratio of 25:1. The carrier gas is nitrogen with a flow rate of 2.4ml/min, hydrogen with a flow rate of 60 ml/min, air with a flow rate of 60 ml/min. The gasification chamber temperature is 250 ℃ The detector temperature is 300 ℃ Solid phase microextraction conditions; Prepare a mixture of five organic phosphorus pesticides with pure water at the required concentration for the experiment day and night, and take 15 ml for extraction testing The peak order is dichlorvos, dichlorvos, levodopa, methyl parathion, and parathion
4、 GC-6890 gas chromatograph for chromatographic analysis of pesticide residues:
4.1 Instruments and reagents: GC-6890 gas chromatograph; Gas chromatography workstation; Quartz capillary column (30m × 0.25mm × 0.25 μ m), gas generator, standard, etc.
4.2. Chromatographic conditions: The carrier gas is high-purity helium gas, the pre column pressure is 80KPa, the column flow rate is 1.2 mL/min, and the injection method is non split Import temperature: 230 ℃, transmission line temperature: 250 ℃ Column temperature program: Initial temperature of 80 ℃, hold for 1 minute, heat up to 250 ℃ at a rate of 10 ℃/min, hold for 7 minutes.
4.3. Sample extraction and purification: Take about 100g and place it in a tissue grinder to crush the homogenate. Accurately weigh 50g of the homogenate and add 100ml of n-hexane. Ultrasonic extraction is carried out for 15nm, filter and leave the filtrate. Then add 50ml of n-hexane to the filter residue for secondary extraction. Combine the filtrate and dry it with anhydrous sodium sulfate. Concentrate it to 3ml using a rotary evaporator and wait for purification Sample purification: The sample is purified by chromatography column Add 2cm thick anhydrous sodium sulfate to both ends of the chromatography column, fill the middle with about 10g of Florisil soil, pre rinse with 30ml of n-hexane, transfer the concentrated extract to the column, rinse with n-hexane/ethyl acetate (95/5, V/V), collect 25ml of eluent, concentrate and make up to 1ml.