Method for detecting sincalide in fruits
阅读说明：本技术 一种水果中辛菌胺的检测方法 (Method for detecting sincalide in fruits ) 是由 李青 于 2020-12-18 设计创作，主要内容包括：本发明属于分析检测领域,公开了一种水果中辛菌胺的检测方法。该方法包括以下步骤：(1)称取样品于离心管中,加入水、乙腈和萃取盐包,振荡混合均匀后再超声提取,然后离心分离,取上清液,将上清液用氮气吹干后,再用乙腈定容,得到测定液；(2)将辛菌胺标准品用乙腈配成一系列浓度的标准工作液,然后经液相色谱质谱仪进行测定,以标准工作液的定量离子峰面积对其相应浓度进行回归分析,得到标准工作曲线；(3)将测定液按步骤(2)中相同条件经液相色谱质谱仪进行测定,计算得到样品中辛菌胺的残留量。本发明适用于水果中辛菌胺的残留量检测,操作过程快速简便,检测精度较高,能够很好地提供检测技术支撑。(The invention belongs to the field of analysis and detection, and discloses a method for detecting sincalide in fruits. The method comprises the following steps: (1) weighing a sample in a centrifuge tube, adding water, acetonitrile and an extraction salt bag, oscillating, mixing uniformly, then carrying out ultrasonic extraction, then carrying out centrifugal separation, taking supernatant, drying the supernatant by using nitrogen, and then carrying out constant volume by using acetonitrile to obtain a measurement solution; (2) preparing a series of standard working solutions with a series of concentrations by using acetonitrile for a Xinjunan standard substance, then determining by using a liquid chromatography mass spectrometer, and carrying out regression analysis on the corresponding concentrations by using the quantitative ion peak area of the standard working solutions to obtain a standard working curve; (3) and (3) determining the determination solution by a liquid chromatography mass spectrometer under the same conditions in the step (2), and calculating to obtain the residual quantity of the sincalide in the sample. The method is suitable for detecting the residual quantity of the sincalide in the fruits, has the advantages of quick and simple operation process and higher detection precision, and can provide a detection technology support well.)
1. A method for detecting sincalide in fruits is characterized by comprising the following steps:
(1) a pretreatment process: weighing a sample in a centrifuge tube, adding water, acetonitrile and an extraction salt bag, oscillating, mixing uniformly, then carrying out ultrasonic extraction, then carrying out centrifugal separation to obtain a supernatant, taking part of the supernatant, drying with nitrogen, and then carrying out constant volume with acetonitrile to obtain a measurement solution;
(2) acquisition of a standard curve: preparing a series of standard working solutions with a series of concentrations by using acetonitrile for a Xinjunan standard substance, determining the standard working solutions by using a liquid chromatography mass spectrometer to obtain corresponding quantitative ion peak areas, and performing regression analysis on the corresponding concentrations by using the quantitative ion peak areas of the standard working solutions to obtain a standard working curve;
(3) determination and analysis of results: and (3) measuring the measurement liquid obtained in the step (1) by a liquid chromatography mass spectrometer under the same conditions in the step (2), measuring the peak area of a quantitative ion of the Xinjunan in the measurement liquid, substituting the peak area into a standard working curve to obtain the content of the Xinjunan in the measurement liquid, and calculating according to the mass of the sample represented in the measurement liquid to obtain the residual amount of the Xinjunan in the sample.
2. The method for detecting sincalide in fruits according to claim 1, wherein:
the extraction salt bag in the step (1) is composed of anhydrous magnesium sulfate, sodium chloride, sodium citrate, disodium hydrogen citrate and ethylenediamine-N-propylsilanized silica gel in a mass ratio of 1:1:0.1:0.05:0.05-1:2:0.5:0.5: 0.5.
3. The method for detecting sincalide in fruits according to claim 1, wherein:
in the step (1), the dosage of the sample, water, acetonitrile and the extraction salt package meets the following requirements: for each 10g sample, 5-20mL of water, 15-50mL of acetonitrile and 5-25g of extraction salt package are added.
4. The method for detecting sincalide in fruits according to claim 1, wherein:
the extraction salt bag in the step (1) consists of anhydrous magnesium sulfate, sodium chloride, sodium citrate, disodium hydrogen citrate and ethylenediamine-N-propyl silanized silica gel in a mass ratio of 1:1:0.2:0.1: 0.1;
in the step (1), the dosage of the sample, water, acetonitrile and the extraction salt package meets the following requirements: for each 10g sample, 5mL of water, 20mL of acetonitrile, and 12g of extraction salt package were added.
5. The method for detecting sincalide in fruits according to claim 1, wherein:
the ultrasonic extraction time in the step (1) is 20 min;
the centrifugation in the step (1) is performed at 12000rpm for 3-10min in 5000-.
6. The method for detecting sincalide in fruits according to claim 1, wherein:
the step of blowing part of the supernatant liquid by nitrogen gas in the step (1) refers to blowing the supernatant liquid by nitrogen gas in water bath at 40 ℃.
7. The method for detecting sincalide in fruits according to claim 1, wherein:
the series of concentrations of the standard working solution in the step (2) are respectively 10, 20, 50, 100 and 200 ng/mL.
8. The method for detecting sincalide in fruits according to claim 1, wherein:
the liquid phase conditions in the liquid chromatogram mass spectrometer in the step (2) are as follows:
column chromatography was C18(2.6 μm,21mm x 100mm), mobile phase a was 0.1% formic acid water, phase B was acetonitrile, flow rate was 0.4mL/min, column temperature: 40 ℃, injection volume: 2uL, gradient elution procedure as shown in Table 1 below:
TABLE 1 liquid chromatography gradient conditions
。
9. The method for detecting sincalide in fruits according to claim 1, wherein:
the mass spectrum conditions in the step (2) are as follows:
ionization mode: ESI; a positive ion mode; air curtain air: 30.0 Psi; and (3) collision gas spraying: 9.0; ionization voltage: positive ion 4500V; spraying mist: 55 Psi; temperature of the desolventizing gas: 550 ℃; auxiliary heating gas: 55 Psi;
other mass spectral conditions are shown in table 2 below:
TABLE 2 other Mass Spectrometry conditions
Quantification of ions.
10. The method for detecting sincalide in fruits according to claim 1, wherein:
the residual quantity of the sincalide in the sample in the step (3) is calculated according to the following formula:
in the formula:
x: the content of sincalide in the sample is milligram per kilogram;
c: measuring the concentration of the sincalide in the solution, wherein the unit is nanogram per milliliter;
v: fixing the volume, namely fixing the volume of the test solution obtained in the step (1) by using acetonitrile, wherein the unit is milliliter;
m: weighing a sample, wherein the unit is gram;
f: the dilution factor, i.e. the ratio of the volume of all supernatants in step (1) to the volume of the part of the supernatant tested in step (1).
Technical Field
The invention belongs to the field of analysis and detection, and particularly relates to a method for detecting sincalide in fruits.
Background
The chemical name of the Xinjunan is N, N-di-N-octyl diethylenetriamine, the Xinjunan is a broad-spectrum and low-toxicity bactericide developed in China, and has obvious killing and inhibiting effects on various plant fungi, bacteria and viruses causing crop diseases. Is suitable for preventing and treating various diseases of tobacco, apple, rice, pepper and cotton, in particular to virus diseases. The food limit requirement in the national food safety standard GB 2763-2019 is that no detection method is specified, no related detection standard exists at home at present, the patent and research documents are few, most of the research is carried out by using a liquid chromatograph, and the research of other detection methods needs to be enhanced. At present, a supervision agency cannot effectively supervise the project, and needs support of related detection technologies urgently.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide the method for detecting the content of the Xinjunan in the fruits, which comprises relevant technical indexes such as detection limit, precision, accuracy, quantitative limit and the like.
The purpose of the invention is realized by the following scheme:
a method for detecting sincalide in fruits comprises the following steps:
(1) a pretreatment process: weighing a sample in a centrifuge tube, adding water, acetonitrile and an extraction salt bag, oscillating, mixing uniformly, then carrying out ultrasonic extraction, then carrying out centrifugal separation to obtain a supernatant, taking part of the supernatant, drying with nitrogen, and then carrying out constant volume with acetonitrile to obtain a measurement solution;
(2) acquisition of a standard curve: preparing a series of standard working solutions with a series of concentrations by using acetonitrile for a Xinjunan standard substance, determining the standard working solutions by using a liquid chromatography mass spectrometer to obtain corresponding quantitative ion peak areas, and performing regression analysis on the corresponding concentrations by using the quantitative ion peak areas of the standard working solutions to obtain a standard working curve;
(3) determination and analysis of results: and (3) measuring the measurement liquid obtained in the step (1) by a liquid chromatography mass spectrometer under the same conditions in the step (2), measuring the peak area of a quantitative ion of the Xinjunan in the measurement liquid, substituting the peak area into a standard working curve to obtain the content of the Xinjunan in the measurement liquid, and calculating according to the mass of the sample represented in the measurement liquid to obtain the residual amount of the Xinjunan in the sample.
The extraction salt package in the step (1) is composed of anhydrous magnesium sulfate, sodium chloride, sodium citrate, disodium hydrogen citrate and ethylenediamine-N-propylsilanized silica gel (PSA) in a mass ratio of 1:1:0.1:0.05:0.05-1:2:0.5:0.5, and preferably composed of anhydrous magnesium sulfate, sodium chloride, sodium citrate, disodium hydrogen citrate and ethylenediamine-N-propylsilanized silica gel (PSA) in a mass ratio of 1:1:0.2:0.1: 0.1.
In the step (1), the dosage of the sample, water, acetonitrile and the extraction salt package meets the following requirements: 5-20mL of water, 15-50mL of acetonitrile and 5-25g of extraction salt package are added for each 10g of sample, and 5mL of water, 20mL of acetonitrile and 12g of extraction salt package are preferably added for each 10g of sample.
The time of ultrasonic extraction in the step (1) is preferably 20 min; the influence of the ultrasonic power on the extraction effect is small, so that the ultrasonic power is not limited;
the centrifugation in the step (1) refers to centrifugation at 12000rpm for 3-10min and 5000-; centrifugation is preferably carried out at 8000rpm for 3 min.
Blowing part of the supernatant fluid by nitrogen in the step (1), preferably blowing the supernatant fluid by nitrogen in a water bath at 40 ℃; the volume of the partial supernatant is preferably 1/4 based on the total supernatant volume, i.e. the subsequent dilution factor is preferably 4.
The volume fixed by acetonitrile in the step (1) is preferably fixed to 1 mL.
The series of concentrations of the standard working solution in the step (2) are preferably the concentrations of the standard working solution of 10, 20, 50, 100 and 200ng/mL respectively.
The liquid phase conditions in the liquid chromatogram mass spectrometer in the step (2) are as follows:
mobile phase: a: 0.1% formic acid water; b: acetonitrile
Column chromatography was C18(2.6 μm,21mm x 100mm), mobile phase a was 0.1% (V/V) formic acid water, phase B was acetonitrile, flow rate was 0.4mL/min, column temperature: 40 ℃, injection volume: 2uL, gradient elution procedure as shown in Table 1:
TABLE 1 liquid chromatography gradient conditions
Time/min
Mobile phase A
Mobile phase B
0
90％
10％
0.5
90％
10％
1
80％
20％
2.5
10％
90％
3
10％
90％
3.1
90％
10％
4
90％
10％
The mass spectrum conditions in the step (2) are as follows:
ionization mode: ESI; a positive ion mode; air curtain gas (CUR): 30.0 Psi; jet impingement (CAD): 9.0; ionization voltage (IS): positive ion 4500V; spray Gas (GSI): 55 Psi; desolventizing vapor Temperature (TEM): 550 ℃; auxiliary heating Gas (GSI): 55 Psi.
Other mass spectral conditions are shown in table 2:
TABLE 2 other Mass Spectrometry conditions
Quantitative ions
The residual quantity of the sincalide in the sample in the step (3) is calculated according to the following formula:
in the formula:
x: the content of sincalide in the sample is milligrams per kilogram (mg/kg);
c: measuring the concentration of the octopamine in nanograms per milliliter (ng/mL) in the solution;
v: fixing the volume, namely fixing the volume of the test solution obtained in the step (1) by using acetonitrile, wherein the unit is milliliter (mL);
m: sample weighing in grams (g);
f: the dilution factor, i.e. the ratio of the volume of all supernatants in step (1) to the volume of the part of the supernatant tested in step (1).
Compared with the prior art, the invention has the following advantages and beneficial effects:
the method is suitable for detecting the residual quantity of the sincalide in the fruits, has the advantages of quick and simple operation process and higher detection precision, and can provide a detection technology support well.
Drawings
FIG. 1 is a liquid phase chromatogram with a standard concentration of octopamine of 200 ng/mL.
FIG. 2 is a mass spectrum of the octylamine standard substance.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The reagents used in the examples are commercially available without specific reference. Wherein acetonitrile (chromatographically pure); methanol (chromatographically pure); ultrapure water (first-grade water quality); formic acid (99%); magnesium sulfate (analytical grade); sodium citrate (analytical grade); disodium hydrogen citrate (analytically pure); sodium chloride (analytically pure).
Preparation of standard solutions in the examples:
standard stock solutions: the standard product of the Xinjunan, CAS 57413-95-3, the purity is more than or equal to 99%. Accurately weighing 0.01g of octopamine standard substance in a 10mL volumetric flask, adding acetonitrile to dissolve, and fixing the volume to the scale. Standard stock solutions were prepared at a concentration of 1000. mu.g/mL. Storing at-18 deg.C for 6 months.
Standard working solution: accurately transferring 0.1mL of standard stock solution into a 10mL volumetric flask, diluting to constant volume with acetonitrile, preparing into standard intermediate solution with concentration of 10 μ g/mL, storing at-18 deg.C, and prolonging the effective period for 1 month.
The equipment used in the examples is as follows: high performance liquid chromatography mass spectrometer (AB 4500); an ultra-high speed refrigerated centrifuge; a nitrogen blowing instrument; a vortex oscillator; electronic balance (0.0001 g); PSA; 0.22 μm organic filter.
Example 1
(1) Pretreatment process
Weighing 10g of sample in a centrifuge tube, sequentially adding 5mL of water, 20mL of acetonitrile and an extraction salt bag, oscillating for 5min, ultrasonically extracting for 20min, centrifuging for 3min at 8000rpm to obtain 20mL of supernatant, taking out 5mL of supernatant, slowly drying with nitrogen in a water bath at 40 ℃, diluting to 1mL with acetonitrile, and performing on-machine analysis.
Extracting salt package: 5g of anhydrous magnesium sulfate, 5g of sodium chloride, 1g of sodium citrate, 0.5g of disodium hydrogen citrate, 500mg of ethylenediamine-N-propylsilanized silica gel (PSA).
(2) Arrangement of standard curves
Standard working solutions are prepared into standard working determination solutions with the concentrations of 10, 20, 50, 100 and 200ng/mL, and the 5 groups of standard working determination solutions are respectively determined by a liquid chromatography mass spectrometer AB4500, wherein the liquid phase conditions are as follows:
column C18(2.6 μm,21mm x 100mm), mobile phase: a: 0.1% formic acid water; b: acetonitrile, flow rate 0.4mL/min, column temperature: 40 ℃, injection volume: 2uL, gradient elution procedure as shown in Table 1:
TABLE 1 liquid chromatography gradient conditions
Time/min
Mobile phase A
Mobile phase B
0
90％
10％
0.5
90％
10％
1
80％
20％
2.5
10％
90％
3
10％
90％
3.1
90％
10％
4
90％
10％
The mass spectrum conditions are as follows:
ionization mode: ESI; a positive ion mode; air curtain gas (CUR): 30.0 Psi; jet impingement (CAD): 9.0; ionization voltage (IS): positive ion 4500V; spray Gas (GSI): 55 Psi; desolventizing vapor Temperature (TEM): 550 ℃; auxiliary heating Gas (GSI): 55 Psi.
Other mass spectral conditions are shown in table 2:
TABLE 2 other Mass Spectrometry conditions
Quantitative ions
The obtained quantitative ion peak area was taken as the ordinate, the concentration of the corresponding standard working measurement solution was taken as the abscissa, and a standard working curve was drawn, and the resulting standard working curve was defined by the equation y of 6598.11688x +8345.58466 and R of 0.99885.
(3) Determination and result analysis
And (3) measuring the sample liquid obtained after the pretreatment in the step (1) by a liquid chromatography mass spectrometer under the same conditions in the step (2), measuring the quantitative ion peak area of the Xinjunan in the measured liquid, substituting the quantitative ion peak area into a standard curve to obtain the content of the Xinjunan in the measured liquid, and calculating according to the mass of the sample represented in the measured liquid to obtain the residual amount of the Xinjunan in the sample.
Weighing 3 parts of fresh apple (red Fuji) and banana (rice banana) samples respectively, uniformly preparing the samples into slurry, then placing the slurry in a centrifuge tube, operating according to the steps (1) to (3), wherein the detection data are shown in the following table 3:
TABLE 3 test results for apple and banana samples
Sample (I)
Test results (mg/kg)
Apple-1
ND
Apple-2
ND
Apple-3
ND
Banana-1
ND
Banana-2
ND
Banana-3
ND
(4) Precision and recovery experiments
Weighing 10 parts of fresh apple (red Fuji) sample with the same mass, uniformly preparing into a homogenate substance, accurately adding a standard solution with the same volume, and performing a standard recovery rate experiment according to the steps (1) to (3), wherein the detection data and the recovery rate are shown in the following table 4:
table 410 detection data and recovery rates for apple samples
Sample (I)
Addition concentration (ng/mL)
Determination of concentration (ng/mL)
Recovery (%)
Apple-1
50.00
47.77
95.54
Apple-2
50.00
53.09
106.18
Apple-3
50.00
48.01
96.02
Apple-4
50.00
49.89
99.78
Apple-5
50.00
51.23
102.46
Apple-6
50.00
46.90
93.8
Apple-7
50.00
49.09
98.18
Apple-8
50.00
49.23
98.46
Apple-9
50.00
47.88
95.76
Apple 10
50.00
49.87
99.74
As can be seen from Table 4, the recovery rate of the method is between 93.8% and 106.18%, and the recovery rate is high, so that the method has high stability, and can well meet the detection requirement of residual quantity of sincalide in fruits.
(5) Detection limit and quantification limit
Adding standard solutions with different concentrations into a blank fresh apple (red Fuji) matrix, then operating according to the steps (1) to (3), calculating a detection limit by using a method of 3 times of signal-to-noise ratio (S/N) of a chromatographic peak of the standard solution with the lowest concentration (10ng/mL), and calculating a quantitative limit by using a method of 10 times of the signal-to-noise ratio (S/N), wherein the detection limit of the method is 0.01mg/kg, and the quantitative limit is 0.03 mg/kg.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.