CN103278555A - Detection method for residual amount of mancozeb in foodstuff - Google Patents

Abstract

The invention discloses a detection method for a residual amount of mancozeb in foodstuff. The detection method comprise the steps: firstly, preparing EDTA solution, extracting a sample by the EDTA solution for two times, centrifuging after merging the two extracts, passing the centrifuging supernatant through a 0.22 microns filter membrane, and detecting by using a liquid chromatography inductively coupled plasma mass spectrometer (LC-ICP-MS). The detection method has the characteristics of speediness, accuracy, short detection period, and lower detection limit and higher accuracy degree.

Description

Mancozeb residual quantity detection method in a kind of food

Technical field

The invention belongs to the food inspection technical field, especially relate to Mancozeb residual quantity detection method in a kind of food.

Background technology

Mancozeb is widely used agricultural chemicals in the world, and various countries all are provided with strict residual benchmark in food; The assay method of the residual quantity of Mancozeb in food mainly is vapor-phase chromatography and liquid phase chromatography at present at present, these methods have a common shortcoming to need exactly the Mancozeb derivatization is detected, and the derivatization process is comparatively loaded down with trivial details, reaction not exclusively, the time of deriving is long, the consumption amount of reagent is big, can't guarantee to provide in the short time testing result accurately.

Summary of the invention

The objective of the invention is to improve the deficiency of prior art and provide quick and precisely, shorten sense cycle, obtain Mancozeb residual quantity detection method in the food of accuracy of lower detection limit and Geng Gao.

The object of the present invention is achieved like this, and Mancozeb residual quantity detection method in a kind of food is characterized in that this method may further comprise the steps:

The preparation of a, EDTA solution: take by weighing 74.4gEDTA-Na2, with the water-soluble solution of 600-700mL, regulating the pH value with the NaOH of 1mol/L is 9.6-10, and the water constant volume is to 1L;

B, extraction: take by weighing sample that 20g smashs to pieces in the 250mL triangular flask, add the EDTA solution that 100mL prepares, between 7.5-8.0, ultrasonic extraction 20min is transferred in the centrifuge tube with 2mol/L salt acid for adjusting pH value, centrifugal 5 min under 4000 r/min, shift supernatant in the 250mL triangular flask, the sample residue extracts with the EDTA solution of 50 mL again, and step is the same, merge behind the extracted twice liquid centrifugally, getting supernatant, to cross 0.22 micron filter membrane to be measured;

C, detection: use instrument: liquid chromatography inductivity coupled plasma mass spectrometry combined instrument (LC-ICP-MS)

Instrument model: liquid chromatograph (LC): Agilent1260; Icp ms (ICP-MS): Agilent7700S; Liquid chromatography inductivity coupled plasma mass spectrometry combined instrument (HPLC-ICP-MS) running parameter: radio-frequency power: 1550 W, sampling depth: 10.0 mm, carrier gas, flow velocity: argon gas 99.99%, 1.08L/min, atomization temperature: 2 ℃, sample cone: platinum awl, analytical column: Agilent TC-C18 250 mm * 4.6mm 5 μ m, flow velocity: 0.6mL/min, sample size: 20 μ L, tuning mode: no gas pattern, sample drainage pattern: TRA.

 

Compared with the prior art the present invention has following distinguishing feature and good effect:

1. extracting link, the purpose of this step invention is in order to reduce cost, to shorten sense cycle, reduce the use of medicine, being more conducive to environmental protection.Advantage is to have reduced antioxidant L-halfcystine with respect to traditional detection method, the use of methyl esterification reagent-iodomethane, and iodomethane is not soluble in water, is unfavorable for environmental protection.Reduced and derived and purification process.Reduce the use of medicine, saved cost, shortened detection time, improved work efficiency.

2. shorten greatly detection time, be product to be tested with the potato, with traditional technique in measuring, detecting Mancozeb content is 0.045mg/kg, detect a sample required time 3.5h, detect with this method, it is 0.047mg/kg that same sample detects Mancozeb content, detects a sample required time 1.0h; Detection limit reduces, and is example with the French bean, and with classic method (0.01mg/kg) detection limit, testing result detects with this method for not detecting (being lower than detection limit), and testing result is 0.006mg/kg; Save cost, classic method generally needs to purify, and derives etc., and it is big to consume amount of reagent, the cost height, and our rule does not need to purify and derives etc., and cost is low.

The accuracy of the inventive method, precision and detection limit are analyzed as follows:

Add 0.02mg/kg, 0.04mg/kg in spinach, French bean, the potato respectively, the 0.08mg/kg standard sample of pesticide is done to add and is reclaimed, each contents level repeats 3 times, the average recovery rate of resulting Mancozeb and relative standard deviation: when the interpolation level in the 0.02-0.08mg/kg scope, the agricultural chemicals recovery is at 70%-110%, relative standard deviation is 0.7%-20.0%, n=3, the recovery and relative standard deviation all meet agricultural residual detection requirement, the agricultural chemicals minimum detectability is 0.005mg/kg, concrete data such as following table:

Table 1 spinach average recovery rate and relative standard deviation n=3

Table 2 French bean average recovery rate and relative standard deviation n=3

Table 3 potato average recovery rate and relative standard deviation n=3

Description of drawings

Below in conjunction with drawings and Examples the present invention is described in further detail.

Fig. 1 is Mancozeb standard items chromatograms

Fig. 2 adds recovery LC-ICP-MS chromatogram for spinach.

Embodiment

Embodiment 1, and Mancozeb residual quantity detection method in a kind of food is the preparation of at first carrying out EDTA solution, is to take by weighing 74.4gEDTA-Na2, and with the water-soluble solution of 600-700mL, regulating the pH value with the NaOH of 1mol/L is 9.6-10, and the water constant volume is to 1L; Extract: take by weighing sample that 20g smashs to pieces in the 250mL triangular flask, add the EDTA solution that 100mL prepares, between 7.5-8.0, ultrasonic extraction 20min is transferred in the centrifuge tube with 2mol/L salt acid for adjusting pH value, centrifugal 5 min under 4000 r/min, shift supernatant in the 250mL triangular flask, the sample residue extracts with 50 mLEDTA solution again, and step is the same, merge behind the extracted twice liquid centrifugally, getting supernatant, to cross 0.22 micron filter membrane to be measured; Detect: use instrument: liquid chromatography inductivity coupled plasma mass spectrometry combined instrument (LC-ICP-MS), instrument model: liquid chromatograph (LC): Agilent1260; Icp ms (ICP-MS): Agilent7700S; Liquid chromatography inductivity coupled plasma mass spectrometry combined instrument (HPLC-ICP-MS) running parameter: radio-frequency power: 1550W, sampling depth: 10.0 mm, carrier gas, flow velocity: argon gas 99.99%, 1.08L/min, atomization temperature: 2 ℃, sample cone: platinum awl, analytical column: Agilent TC-C18 250 mm * 4.6mm 5 μ m, flow velocity: 0.6 mL/min, sample size: 20 μ L, tuning mode: no gas pattern, sample drainage pattern: TRA.

This example is product to be tested with the potato, take by weighing sample that 20g smashs to pieces in the 250mL triangular flask, add the EDTA solution that 100 mL prepare, regulate the pH value to 7.5-8.0, ultrasonic extraction 20min, be transferred in the centrifuge tube, centrifugal 5 min under 4000 r/min shift supernatant in the 250mL triangular flask, the sample residue is used 50 mLEDTA solution again, step is the same, merges behind the extracted twice liquid centrifugally, and getting supernatant, to cross 0.22 micron filter membrane to be measured, liquid chromatography inductivity coupled plasma mass spectrometry combined instrument (HPLC-ICP-MS) running parameter: radio-frequency power: 1550 W, sampling depth: 10.0 mm, carrier gas, flow velocity: argon gas 99.99%, 1.08L/min, atomization temperature: 2 ℃, sample cone: platinum awl, analytical column: Agilent TC-C18 250 mm * 4.6mm 5 μ m, flow velocity: 0.6mL/min, sample size: 20 μ L; Tuning mode: no gas pattern, sample drainage pattern: TRA.

This testing sample detects with classic method, sample has the Mancozeb 0.045mg/kg of low concentration, is 0.047mg/kg according to the present embodiment detection method value of detecting, above-mentioned example explanation, this detection method does not have significant difference in testing result, illustrates that this method has obtained one well quantitatively.

Embodiment 2, Mancozeb residual quantity detection method in a kind of food, this example is product to be tested with the French bean, take by weighing sample that 20g smashs to pieces in the 250mL triangular flask, add the EDTA solution that 100 mL prepare, regulate the pH value to 7.5-8.0, ultrasonic extraction 20min, be transferred in the centrifuge tube, centrifugal 5min under 4000 r/min shifts supernatant in the 250mL triangular flask, the sample residue extracts with the EDTA solution of 50mL again, step is the same, merges behind the extracted twice liquid centrifugally, and getting supernatant, to cross 0.22 micron filter membrane to be measured, liquid chromatography inductivity coupled plasma mass spectrometry combined instrument (HPLC-ICP-MS) running parameter: radio-frequency power: 1550 W, sampling depth: 10.0 mm, carrier gas, flow velocity: argon gas 99.99%, 1.08L/min, atomization temperature: 2 ℃, sample cone: platinum awl, analytical column: Agilent TC-C18 250 mm * 4.6mm 5 μ m, flow velocity: 0.6mL/min, sample size: 20 μ L; Tuning mode: no gas pattern, sample drainage pattern: TRA.

This testing sample detects with classic method, sample does not detect Mancozeb, is 0.006mg/kg according to the present embodiment detection method value of detecting, above-mentioned example explanation, this detection method is better than classic method at detection limit, illustrates that this method has lower quantitative limit.

Above-described example only is that the specific embodiment of the present invention is described, and is not that scope of the present invention is limited.

Claims (1)

1. Mancozeb residual quantity detection method in the food is characterized in that this method may further comprise the steps:

The preparation of EDTA solution: take by weighing 74.4gEDTA-Na2, with the water-soluble solution of 600-700mL, regulating the pH value with the NaOH of 1mol/L is 9.6-10, and the water constant volume is to 1L;

B, extraction: take by weighing sample that 20g smashs to pieces in the 250mL triangular flask, add the EDTA solution that 100mL prepares, between 7.5-8.0, ultrasonic extraction 20min is transferred in the centrifuge tube with 2mol/L salt acid for adjusting pH value, centrifugal 5 min under 4000 r/min, shift supernatant in the 250mL triangular flask, the sample residue extracts with the EDTA solution of 50 mL again, and step is the same, merge behind the extracted twice liquid centrifugally, getting supernatant, to cross 0.22 micron filter membrane to be measured;

C, detection: use instrument: liquid chromatography inductivity coupled plasma mass spectrometry combined instrument (LC-ICP-MS)

Instrument model: liquid chromatograph (LC): Agilent1260; Icp ms (ICP-MS): Agilent7700S; Liquid chromatography inductivity coupled plasma mass spectrometry combined instrument (HPLC-ICP-MS) running parameter: radio-frequency power: 1550 W, sampling depth: 10.0 mm, carrier gas, flow velocity: argon gas 99.99%, 1.08L/min, atomization temperature: 2 ℃, sample cone: platinum awl, analytical column: Agilent TC-C18 250 mm * 4.6mm 5 μ m, flow velocity: 0.6mL/min, sample size: 20 μ L, tuning mode: no gas pattern, sample drainage pattern: TRA.

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