Method for detecting profenofos in orange juice

Abstract

The invention relates to a method for detecting profenofos in orange juice, which comprises the following steps: S1, pouring an orange juice sample into a polypropylene centrifuge tube, then adding a profenofos standard solution to prepare a mixed solution with the concentration of 100 [mu] g.L <-1 >, and carrying out ultrasonic mixing; s2, adding amorphous UIO-66 into the mixed solution subjected to ultrasonic mixing in the step S1, and performing oscillation adsorption by an oscillator; s3, centrifugal separation is conducted, supernate is poured away, a solid material is left, and the solid material is added into methanol to be subjected to ultrasonic elution; and S4, centrifuging the collected eluent, and directly carrying out LC-UV detection on the supernate. The amorphous UIO-66 adsorbent provided by the invention has excellent stability and adjustable performance, and realizes efficient enrichment and adsorption of profenofos to maximize the extraction efficiency and improve the accuracy of a detection result.

Description

Technical Field

[0001] The invention relates to the technical field of chemical detection, and in particular to a method for detecting propylbromophos in orange juice. Background Art

[0002] As an organophosphorus pesticide, profenofos is widely used in modern agriculture, horticulture and households, making it an important part of the global pesticide usage. However, the potential toxicity of profenofos, including hormone interference, cytotoxicity and immunotoxicity, has made its impact on the human body and the environment a concern. In particular, the residue problem of profenofos in foods such as orange juice directly threatens the health and safety of consumers. Therefore, accurate and efficient detection of profenofos residues in orange juice has become an important challenge in the current food safety field. Several analytical methods such as high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) have been applied to the determination of profenofos in food matrices. Sample preparation is of great significance in the analysis of profenofos residues, and its purpose is to concentrate the target analytes and eliminate matrix interference. Traditional liquid-liquid extraction (LLE) and solid phase extraction (SPE) methods are time-consuming, complex and costly, and contain a large amount of potentially toxic solvents, which have adverse effects on health. Dispersive solid phase extraction (DSPE) is an extraction method that performs extraction in a bulk solution, which can reduce the extraction time and simplify the extraction process. Among the sample pretreatment methods, the choice of adsorbent is crucial. In the extraction process, the performance of the adsorbent is a key factor that directly affects the accuracy and reliability of the test results. However, current adsorbents have limitations in adsorption capacity.

[0003] Reference 1 discloses a method for detecting organophosphorus pesticides in fruit juice samples using a polycarbonate-based dispersed solid phase extraction technique combined with a dispersed liquid-liquid microextraction technique. This method uses highly toxic and hazardous solvents such as carbon tetrachloride during the extraction process, which poses potential risks to the environment and operator health.

[0004] Reference 2 discloses a method for detecting pesticides based on partially carbonized cellulose filter paper as a solid phase extraction adsorbent. This method is limited in use when extracting non-polar compounds such as bromophos due to the hydrophilic nature of cellulose. Summary of the invention

[0005] In order to overcome the adsorption capacity limitations of traditional adsorbents, the present invention provides an amorphous UIO-66 adsorbent, which is non-toxic and has a wide range of uses. This material has excellent stability and adjustable performance, and can achieve efficient enrichment and adsorption of bromophos, thereby maximizing the extraction efficiency and improving the accuracy of the detection results.

[0006] The technical solution of the present invention:

[0007] A method for detecting profenofos in orange juice comprises the following steps:

[0008] S1. Pour the orange juice sample into a polypropylene centrifuge tube, then add the bromophos standard solution to a concentration of 100 μg·L -1 The mixed solution is ultrasonically mixed;

[0009] S2, adding amorphous UIO-66 to the mixed solution after ultrasonic mixing in S1, and adsorbing by oscillating on an oscillator;

[0010] S3, centrifugation, pouring out the supernatant, leaving solid materials, adding the solid materials into the eluent for ultrasonic elution; S4, centrifuging the collected eluent, and directly performing LC-UV detection on the supernatant obtained by centrifugation.

[0011] Preferably, in order to reduce the error, the extraction procedures (S1-S4) of all samples are carried out three times, and the concentration of bromophos in orange juice is taken as the average value of the three calculation results.

[0012] Preferably, the volume ratio of the orange juice sample and the bromophos standard solution in S1 is 10000:1, and the concentration of the bromophos standard solution is 1 mg·mL -1 ; The ultrasonic mixing time is not less than 10 minutes, and the ultrasonic frequency is 40KHz.

[0013] Preferably, the volume mL of the mixed solution and the mass mg of the amorphous UIO-66 in S2 is 4:1-5, the oscillation adsorption time is 5-30 min, and the oscillation frequency of the oscillator is 800 rpm.

[0014] Preferably, the eluent in S3 is CH3OH, CH3CN, NH3·H2O / CH3OH or CH3COOH / CH3OH;

[0015] The centrifugal speed is not less than 8000 rpm, and the centrifugal time is not less than 10 min; the ratio of the volume μL of the eluent to the mass mg of the solid material is 6.67-26.7:1.

[0016] Preferably, NH3·H2O / CH3OH in S3 is a mixture of NH3·H2O and CH3OH, CH3COOH / CH3OH is a mixture of CH3COOH and CH3OH, and the volume ratio of CH3COOH to CH3OH is 0.25 to 2:100;

[0017] The ultrasonic elution time is not less than 10 minutes, and the ultrasonic frequency is 40KHz.

[0018] Preferably, the centrifugal speed of the eluent in S4 is not less than 8000 rpm, and the centrifugal time is not less than 10 min.

[0019] Preferably, the preparation method of amorphous UIO-66 described in S2 comprises the following steps:

[0020] S21, acetamide and diethanolamine hydrochloride are mixed to obtain a deep eutectic solvent;

[0021] S22, adding water to the deep eutectic solvent and stirring to obtain a mixed solution of the deep eutectic solvent and water;

[0022] S23, weigh terephthalic acid and zirconium chloride, add them to a mixed solution of deep eutectic solvent and water in S22 for oil bath reaction; S24, centrifuge the reaction solution obtained in S23; after centrifugation, remove the supernatant, add methanol to the centrifuge tube with solid sediment at the bottom, ultrasonically clean for more than 20 minutes, and centrifuge; S24 is repeated twice, and the solid is dried to obtain amorphous UIO-66.

[0023] Preferably, the molar ratio of acetamide to diethanolamine hydrochloride in S21 is 2:1;

[0024] The volume ratio of deep eutectic solvent to water in S22 is 1:0.2;

[0025] In S23, the molar ratio of phthalic acid to zirconium chloride is 1:1, and the volume mL of the deep eutectic solvent and the molar ratio of zirconium chloride are 16.7:0.4;

[0026] The volume ratio of methanol to deep eutectic solvent used for ultrasonic cleaning in S24 is 2:3.

[0027] Preferably, the mixing temperature in S21 is 80-85° C. and the mixing time is 1-1.5 h;

[0028] The temperature of the oil bath in S23 is 100°C and the reaction time is 5 h;

[0029] In S24, the centrifugal speed was 8000 rpm and the centrifugal time was 10 min.

[0030] Beneficial effects of the present invention:

[0031] The UIO-66 prepared by the present invention is used to adsorb different concentrations of bromophos in an aqueous medium, and various kinetic and isotherm models are used to fit the adsorption data, and the inherent mechanism of the adsorption process is revealed in combination with theoretical calculations. The various conditions of sample pretreatment are systematically optimized using a single factor method to maximize the extraction efficiency and improve the accuracy of the test results. The target substances in the sample are quantitatively and qualitatively analyzed using liquid chromatography (LC)-ultraviolet detection (UV). The applicability of the method is evaluated by methodological verification of the established method to facilitate the determination of bromophos residues in commercially available orange juice. The data obtained provide reliable technical support for food safety testing. The present invention provides an amorphous UIO-66 adsorbent, which is non-toxic and has a wide range of uses. This material has excellent stability and adjustable performance, and achieves efficient enrichment and adsorption of bromophos, so as to maximize the extraction efficiency and improve the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a diagram of the method steps of the present invention;

[0033] Figure 2 This is the optimization diagram for the dosage of amorphous UIO-66;

[0034] Figure 3 Optimization diagram for extraction time;

[0035] Figure 4 is the optimization diagram of the eluent type;

[0036] Figure 5 is the optimization diagram of the volume ratio of CH3COOH in CH3OH;

[0037] Figure 6 Optimization diagram for the eluent volume of 1% CH3COOH / CH3OH;

[0038] Figure 7 The typical chromatogram of bromophos obtained by this method. Unspiked orange juice sample after pretreatment (upper line); spiked orange juice sample after pretreatment 10 μg·L -1 (the line below);

[0039] Figure 8 Chromatograms of deionized water treated with amorphous UIO-66 (upper line) and without amorphous UIO-66 (lower line). DETAILED DESCRIPTION

[0040] The raw materials used in the present invention

[0041] Humic acid (HA, ≥90%) and sodium chloride (NaCl, 99.5%) were purchased from Shanghai McLean Biochemical Co., Ltd., China. Profenofos standards were from Panphy Chemicals (Los Angeles, USA). Analytical grade methanol and ethanol were purchased from Tianjin Fuchen Chemical Reagent Co., Ltd., China. Chromatographic grade acetonitrile (ACN) was purchased from MREDA Technology Co., Ltd. (Beijing). Ultrapure water was obtained using a Milli-Q water purification system (Millipore, USA).

[0042] LC-UV detection method

[0043] Profenofos was analyzed using an Agilent 1260 high performance liquid chromatography (HPLC) system (Waldbronn, Germany) equipped with a Hypersil ODS2 column (4.6 mm × 200 mm, 5 μm) at a column temperature of 30 °C. The detection wavelength was 200 nm, and the injection volume was 10 μL. The mobile phase was acetonitrile and water (80 / 20, v / v) at a flow rate of 1.0 mL min -1 All separations were completed within 6 min.

[0044] Synthesis Example of Amorphous UIO-66

[0045] S21, synthesis of eutectic solvent reaction solvent, acetamide as hydrogen bond donor, diethanolamine hydrochloride as acceptor, mixed at 80 °C for 1 h in a molar ratio of 2:1 to obtain a deep eutectic solvent;

[0046] S22, 20 mL of deep eutectic solvent was added to 4 mL of water and stirred to obtain a DES-water mixture;

[0047] The DES-water mixture (20 mL) was transferred into a three-necked flask and a rotor was added for magnetic stirring;

[0048] S23, weigh terephthalic acid H2BDC (molecular weight 166.13, 0.4 mmol, 0.066452 g) and zirconium chloride (molecular weight 233.04, 0.4 mmol, 0.093216 g) and add them into a three-necked flask, place in an oil bath at 100°C, and react for 5 hours;

[0049] S24, transfer the liquid in the flask into a centrifuge tube, rinse the flask with 10-20 mL of methanol, and then transfer it into a centrifuge tube. Centrifuge the flask into two centrifuge tubes at 8000 rpm for 10 min. After centrifugation, remove the supernatant, add 30 mL of methanol, perform ultrasonic cleaning for 20 min, and centrifuge.

[0050] S24 was repeated twice, and the mixture was dried at 60°C for 3 h to obtain a dry powder.

[0051] 1. Example

[0052] Figure 1 The method steps of the present invention are described in detail.

[0053] Embodiment 1

[0054] A method for detecting bromophos in orange juice comprises the following steps: pouring 20 mL of orange juice sample into a 50 mL polypropylene centrifuge tube, and then adding 2 microliters of 1 mg mL -1 Profenofos standard solution, prepared to a concentration of 100 μg·L -1 Mixed solution. After ultrasonic mixing for 10 minutes, 5-25 mg of amorphous UIO-66 was added to the uniformly mixed solution, and the oscillator was oscillated for 20 minutes for full adsorption, and the oscillator's oscillation frequency was 800 rpm. Subsequently, centrifugation was performed at a speed of 8000 rpm for 10 minutes to recover the adsorbent material. The supernatant was poured out and the remaining solid material was eluted with 200 μL of methanol. For full desorption, it was necessary to ultrasonicate in an ultrasonic instrument for 10 minutes. Finally, the collected eluate was centrifuged, and the supernatant was transferred to a 1.5 mL liquid phase vial with a liner for direct LC-UV detection. To reduce errors, the extraction procedures for all samples were performed three times.

[0055] Figure 2 The results show that when the adsorbent dosage increases to 15 mg, the recovery rate of bromophos in orange juice reaches the highest value. If the adsorbent dosage continues to increase, the recovery rate gradually decreases. This may be because the increase in the amount of adsorbent increases the number of active sites, thereby improving the adsorption efficiency of bromophos. When the dosage exceeds 15 mg, the particles agglomerate significantly, and the eluent cannot effectively elute bromophos from the material, reducing the utility of the method. Therefore, 15 mg of amorphous UIO-66 is the optimal adsorbent dosage for subsequent experiments.

[0056] Embodiment 2

[0057] A method for detecting bromophos in orange juice comprises the following steps: pouring 20 mL of orange juice sample into a 50 mL polypropylene centrifuge tube, and then adding bromophos standard solution to prepare a concentration of 100 μg·L -1 mixed solution. After ultrasonic mixing for 10 minutes, 15 mg of amorphous UIO-66 was added to the uniformly mixed solution, and the oscillator was oscillated for 5-30 minutes for full adsorption, and the oscillation frequency of the oscillator was 800 rpm. Subsequently, centrifugation was performed at 8000 rpm for 10 minutes to recover the adsorbent material. The supernatant was poured out and the remaining solid material was eluted with 200 μL of methanol. For full desorption, it was necessary to ultrasonicate in an ultrasonicator for 10 minutes. Finally, the collected eluate was centrifuged, and the supernatant was transferred to a 1.5 mL liquid phase vial with a liner for direct LC-UV detection. To reduce errors, the extraction procedures for all samples were performed three times.

[0058] Figure 3 The results showed that the recovery rate of bromophos reached the maximum value when the adsorption time was 20 minutes. Therefore, in the following experiments, 20 minutes was selected as the optimal extraction time.

[0059] Embodiment 3

[0060] A method for detecting bromophos in orange juice comprises the following steps: pouring 20 mL of orange juice sample into a 50 mL polypropylene centrifuge tube, and then adding bromophos standard solution to prepare a concentration of 100 μg·L -1 After ultrasonic mixing for 10 minutes, 15 mg of amorphous UIO-66 was added to the uniformly mixed solution, and the oscillator was oscillated for 20 minutes for sufficient adsorption, and the oscillator's oscillation frequency was 800 rpm. Subsequently, centrifugation was performed at 8000 rpm for 10 minutes to recover the adsorbent material. The supernatant was discarded and the remaining solid material was eluted with 200 μL CH3OH, CH3CN, NH3·H2O / CH3OH (1% volume fraction NH3·H2O was added to CH3OH) or CH3COOH / CH3OH (1% volume fraction CH3COOH was added to CH3OH). For sufficient desorption, ultrasonication in an ultrasonicator was required for 10 minutes. Finally, the collected eluate was centrifuged, and the supernatant was transferred to a 1.5 mL liquid phase vial with a liner and directly subjected to LC-UV detection. To reduce errors, the extraction procedures for all samples were performed three times.

[0061] This example investigates the effects of four different types of eluents, including CH3OH, CH3CN, NH3·H2O / CH3OH, and CH3COOH / CH3OH, on the extraction effect. Figure 4 As shown in the figure, when CH3COOH / CH3OH solution was used as the eluent, the recovery rate of the target compound was significantly improved. The reason for this behavior may be that the polarity of CH3COOH / CH3OH is similar to that of the measured compound, and based on the principle of similar dissolves, the analyte is more easily dissolved in CH3COOH / CH3OH.

[0062] Embodiment 4

[0063] A method for detecting bromophos in orange juice comprises the following steps: pouring 20 mL of orange juice sample into a 50 mL polypropylene centrifuge tube, and then adding bromophos standard solution to prepare a concentration of 100 μg·L -1Mixed solution. After ultrasonic mixing for 10 minutes, 15 mg of amorphous UIO-66 was added to the uniformly mixed solution, and the oscillator was oscillated for 20 minutes for sufficient adsorption, and the oscillation frequency of the oscillator was 800 rpm. Subsequently, centrifugation was performed at a speed of 8000 rpm for 10 minutes to recover the adsorbent material. The supernatant was poured out, and the remaining solid material was eluted with 200 μL CH3COOH / CH3OH (0.25, 0.5, 1, 1.5, and 2% volume fraction of CH3COOH was added to CH3OH). For sufficient desorption, ultrasonication in an ultrasonic instrument was required for 10 minutes. Finally, the collected eluate was centrifuged, and the supernatant was transferred to a 1.5 mL liquid phase vial with a liner, and LC-UV detection was performed directly. To reduce errors, the extraction procedures for all samples were performed three times.

[0064] The addition of acetic acid changes the pH value and the binding environment of amorphous UIO-66 and bromofos, thereby weakening the interaction forces between bromofos and amorphous UIO-66, such as hydrogen bonding, electrostatic interaction, van der Waals force and hydrophobic interaction. Therefore, the analyte is more likely to be transferred to the eluent, thereby improving the extraction level. Figure 5 As shown in the figure, when 1% volume fraction CH3COOH is added to CH3OH, the recovery rate of the target compound is the highest. Further increasing the proportion of CH3COOH, the recovery rate decreases instead, which may be because the more acidic eluent has a higher polarity, which is greater than the polarity of the analyte. Therefore, this will reduce the solubility of the target compound in the elution solvent. Based on the above conclusions, 1% CH3COOH / CH3OH is the best elution solvent.

[0065] Embodiment 5

[0066] A method for detecting bromophos in orange juice comprises the following steps: pouring 20 mL of orange juice sample into a 50 mL polypropylene centrifuge tube, and then adding bromophos standard solution to prepare a concentration of 100 μg·L -1 Mixed solution. After ultrasonic mixing for 10 minutes, 15 mg of amorphous UIO-66 was added to the uniformly mixed solution, and the oscillator was oscillated for 20 minutes for sufficient adsorption. The oscillator's oscillation frequency was 800 rpm. Then centrifuged at 8000 rpm for 10 minutes to recover the adsorbent material. Pour out the supernatant and elute the remaining solid material with 100-400 μL CH3COOH / CH3OH (1% volume fraction CH3COOH was added to CH3OH). For sufficient desorption, it is necessary to ultrasonicate in an ultrasonic instrument for 10 minutes. Finally, the collected eluate was centrifuged, and the supernatant was transferred to a 1.5 mL liquid phase vial with a liner for direct LC-UV detection. To reduce errors, the extraction procedures for all samples were performed three times.

[0067] like Figure 6As shown in the figure, with the increase of the volume of 1% CH3COOH / CH3OH solution, the recovery rate of bromophos gradually increased, while the recovery rate began to decrease after the eluent exceeded 300 μL. In subsequent experiments, the eluent volume was selected to be 300 μL.

[0068] Best Mode

[0069] A method for detecting bromophos in orange juice comprises the following steps: pouring 20 mL of orange juice sample into a 50 mL polypropylene centrifuge tube, and then adding bromophos standard solution to prepare a concentration of 100 μg·L -1 Mixed solution. After ultrasonic mixing for 10 minutes, 15 mg of amorphous UIO-66 was added to the uniformly mixed solution, and the oscillator was oscillated for 20 minutes for sufficient adsorption. The oscillator's oscillation frequency was 800 rpm. Subsequently, centrifugation was performed at a speed of 8000 rpm for 10 minutes to recover the adsorbent material. The supernatant was poured out, and the remaining solid material was eluted with 300 μL CH3COOH / CH3OH (1% volume fraction of CH3COOH was added to CH3OH). For sufficient desorption, it was necessary to ultrasonicate in an ultrasonic instrument for 10 minutes. Finally, the collected eluate was centrifuged, and the supernatant was transferred to a 1.5 mL liquid phase vial with a liner, and LC-UV detection was performed directly. To reduce errors, the extraction procedures for all samples were performed three times.

[0070] 2. Verification Example of the Accuracy of the Method of the Present Invention

[0071] Under the pretreatment conditions of the optimal embodiment (15 mg amorphous UIO-66, adsorption time 20 min, elution solvent 300 μL 1% CH3COOH / CH3OH), the linear range, recovery rate, repeatability, limit of quantification (LOQ), and limit of detection (LOD) of the method were verified, and the results are shown in Table 1. After the pretreatment extraction procedure, the working solution containing a series of concentrations of bromophos was analyzed by HPLC, and a standard curve was drawn. The linear fitting results showed that bromophos had a linear range of 0.8 to 75 μg·L -1 Within the range of R 2 =0.9905, good linearity. -1 The recoveries of spiked samples were determined at 100% and 200% levels, respectively, and the relative standard deviations (RSDs) were 8.29% and 11.50%, indicating that the method has good accuracy and precision. In addition, the detection limit (LOD) of the method was 0.257 μg·L -1 , which is far lower than the maximum residue level set by the European Union for fruit, and the limit of quantification (LOQ) of the method is 0.389 μg·L -1The LOD and LOQ were calculated experimentally and were defined as the lowest extractable concentration that produced a signal-to-noise ratio of 3 or 10 times. -1 Under the conditions of , the repeatability test was carried out to study the intra-day (n=3) and inter-day (n=3) precision of the method and evaluate it with relative standard deviation (RSD). According to the calculation results, the intra-day precision was 4.04% and the inter-day precision was 6.65%, indicating that the method has good reproducibility. In general, the DSPE method of amorphous UIO-66 has good linearity, low detection limit and high precision for the detection of bromofos in orange juice samples.

[0072] Table 1 Quality analysis parameters and actual sample detection under the optimal embodiment

[0073]

[0074] 3. Actual sample detection example

[0075] Under the extraction conditions of the optimal embodiment, the content of propyl bromide in 5 portions of common orange juice on the market was tested to verify the applicability of the method. Figure 7 LC chromatograms of spiked and unspiked orange juice samples after extraction are shown, with no interference from the sample matrix observed.

[0076] Each sample was analyzed three times to ensure reproducibility. As shown in Table 1, all five orange juice samples showed the presence of bromophos. The concentration of the target substance in different brands of orange juice samples varied, ranging from 4.14 to 31.39 μg·L -1 These test results are basically consistent with the published literature ] As a control, in the chromatograms of deionized water without and after treatment with amorphous UIO-66, no significant peak of the target substance was found within the elution time of the target substance ( Figure 8 ). These results indicate that the developed detection method can effectively extract and sensitively detect trace amounts of profenofos in orange juice samples.

[0077] 4. Comparative Examples

[0078] The present invention is compared with some reported methods for determining pesticides in fruit or vegetable juices. The detection method of the best embodiment is different in the type and amount of adsorbent, the type and amount of elution solvent.

[0079] Table 2 Comparison of the present invention with other pretreatment methods in juice

[0080]

[0081]

[0082] References 1Farajzadeh MA, Sattari Dabbagh M. Development of a dispersive solid phase extraction method based on in situ formation of adsorbent followed by dispersive liquid–liquid microextraction for extraction of some pesticide residues in fruit juice samples[J]. Journal of Chromatography A, 2020, 1627: 461398. (Development of a dispersive solid phase extraction method based on in situ formation of adsorbent followed by dispersive liquid–liquid microextraction for extraction of some pesticide residues in fruit juice samples[J]. Journal of Chromatography A, 2020, 1627: 461398.)

[0083] Reference 2 Bakhshizadeh Aghdam M, Farajzadeh MA, Afshar Mogaddam MR. Partially carbonized cellulose filter paper as a green adsorbent for the extraction of pesticides from fruit juices [J]. Journal of Chromatography A, 2021, 1648: 462220. (Partially carbonized cellulose filter paper as a green adsorbent for the extraction of pesticides from fruit juices [J]. Journal of Chromatography A, 2021 1648: 462220.)

[0084] Reference 3 Bakhshizadeh Aghdam M, Farajzadeh MA, Afshar Mogaddam MR. Facile preparation of carbonized cellulose nanoparticles and their application for the dispersive solid phase extraction prior to dispersive liquid–liquid microextraction of pesticide residues from vegetable and fruit juices [J]. Journal of Food Composition and Analysis, 2022, 110: 104527. (Simple preparation of carbonized cellulose nanoparticles and their application for the dispersive solid phase extraction prior to dispersive liquid–liquid microextraction of pesticide residues from vegetable and fruit juices [J]. Journal of Food Composition and Analysis, 2022, 110: 104527.)

[0085] Reference 4 Gang Z, Cao Y, Zeng Z, et al. Application of novel adsorbents synthesized with polypyrrole in magnetic solid-phase extraction of fungicides from fresh juice and environmental water [J]. Food Chemistry, 2024, 437: 137949.

[0086] Reference 5 Yang X, Zhang H, Liu Y, et al. Multiresidue method for determination of 88 pesticides in berry fruits using solid-phase extraction and gas chromatography–mass spectrometry: Determination of 88 pesticides in berries using SPE and GC–MS [J]. Food Chemistry, 2011, 127(2): 855-865.

[0087] Reference 6Pezhhanfar S, Farajzadeh MA, Hosseini-Yazdi SA, et al. Analytical application of MIL-53 (Al) for the extraction of pesticides from fruit juices following their preconcentration through dispersive liquid-liquid microextraction [J]. Talanta Open, 2022, 5: 100121. (Analytical application of MIL-53 (Al) for the extraction of pesticides from fruit juices following their preconcentration through dispersive liquid-liquid microextraction [J]. Talanta Open, 2022, 5: 100121.)

[0088] Reference 7 Sattari Dabbagh M, Farajzadeh M A. Introduction of a new procedure for the synthesis of polysulfone magnetic nanoparticles and their application in magnetic solid phase extraction for the extraction of some pesticides from fruit and vegetable juices[J]. Microchemical Journal, 2020, 158: 105238. (A new method for the synthesis of polysulfone magnetic nanoparticles and their application in magnetic solid phase extraction for the extraction of some pesticides from fruit and vegetable juices[J]. Microchemical Journal, 2020, 158: 105238.)

[0089] After comparison, the results are listed in Table 2. The present invention requires less adsorbent, has a lower LOD, and shows better or equivalent performance in both recovery and precision. In addition, the current method consumes only 300 μL of eluent volume, which is much lower than most published methods. The sensitivity, accuracy and reliability of the method established by the present invention are good, indicating that the amorphous UIO-66 material of the present invention is suitable for the extraction and enrichment of pesticides and can be actually used for the determination of target content in food matrices.

[0090] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical content of the present invention.

Claims

1. A method for detecting bromophos in orange juice, characterized in that: The following steps are involved: S1. Add bromophos standard solution to the orange juice sample to prepare a concentration of 100 μg·L -1 The mixed solution is ultrasonically mixed; S2, adding amorphous UIO-66 to the mixed solution after ultrasonic mixing in S1, and adsorbing by oscillating on an oscillator; S3, centrifugation, discarding the supernatant, leaving solid material, adding the solid material to the eluent for ultrasonic elution; S4. The collected eluate is centrifuged, and the supernatant obtained by centrifugation is directly subjected to LC-UV detection.

2. The method for detecting profenofos in orange juice according to claim 1, characterized in that: To reduce the error, the extraction procedures (S1-S4) of all samples were carried out three times, and the concentration of bromophos in orange juice was taken as the average of the three calculation results.

3. The method for detecting profenofos in orange juice according to claim 1, characterized in that: The volume ratio of orange juice sample and bromophos standard solution in S1 is 10000:1, and the concentration of bromophos standard solution is 1 mg·mL -1 ; The ultrasonic mixing time is not less than 10 minutes, and the ultrasonic frequency is 40KHz.

4. The method for detecting profenofos in orange juice according to claim 1, characterized in that: The volume mL of the mixed solution in S2 and the mass mg ratio of amorphous UIO-66 are 4:1-5, the oscillation adsorption time is 5-30 min, and the oscillation frequency of the oscillator is 800 rpm.

5. The method for detecting profenofos in orange juice according to claim 1, characterized in that: In S3, the eluent is CH3OH, CH3CN, NH3·H2O / CH3OH or CH3COOH / CH3OH; The centrifugal speed is not less than 8000 rpm, and the centrifugal time is not less than 10 min; the ratio of the volume μL of the eluent to the mass mg of the solid material is 6.67 to 26.7:

1.

6. The method for detecting profenofos in orange juice according to claim 5, characterized in that: In S3, NH3·H2O / CH3OH is a mixture of NH3·H2O and CH3OH, and CH3COOH / CH3OH is a mixture of CH3COOH and CH3OH, with the volume of CH3COOH to CH3OH being 0.25 to 2:100; The ultrasonic elution time is not less than 10 minutes, and the ultrasonic frequency is 40KHz.

7. The method for detecting profenofos in orange juice according to claim 1, characterized in that: The centrifugal speed of the eluent in S4 is not less than 8000 rpm, and the centrifugal time is not less than 10 min.

8. The method for detecting profenofos in orange juice according to claim 1, characterized in that: The preparation method of amorphous UIO-66 described in S2 comprises the following steps: S21, acetamide and diethanolamine hydrochloride are mixed to obtain a deep eutectic solvent; S22, adding water to the deep eutectic solvent and stirring to obtain a mixed solution of the deep eutectic solvent and water; S23, weighing terephthalic acid and zirconium chloride, adding them into a mixed solution of deep eutectic solvent and water in S22 and reacting in an oil bath; S24, centrifuging the reaction solution obtained in S23; after centrifugation, removing the supernatant, adding methanol to the centrifuge tube with solid sediment at the bottom, ultrasonically cleaning for more than 20 minutes, and centrifuging; S24 was repeated twice, and the solid was dried to obtain amorphous UIO-66.

9. The method for detecting profenofos in orange juice according to claim 8, characterized in that: The molar ratio of acetamide to diethanolamine hydrochloride in S21 is 2:1; The volume ratio of deep eutectic solvent to water in S22 is 1:0.2; In S23, the molar ratio of terephthalic acid to zirconium chloride is 1:1, and the volume mL of the deep eutectic solvent and the molar ratio of zirconium chloride are 16.7:0.4; The volume ratio of methanol to deep eutectic solvent used for ultrasonic cleaning in S24 is 2:

3.

10. The method for detecting profenofos in orange juice according to claim 8, characterized in that: In S21, the mixing temperature is 80-85°C and the mixing time is 1-1.5h; The temperature of the oil bath in S23 is 100°C and the reaction time is 5 h; In S24, the centrifugal speed was 8000 rpm and the centrifugal time was 10 min.

Images