Abstract
A method for simultaneous determination of ten pyrethroid insecticides residues in edible mushrooms was developed. The samples were pretreated by a quick, easy, cheap, effective, rugged (QuEChERS) method. The ten pyrethroid insecticides were extracted from six kinds of edible mushrooms using acetonitrile and subsequently cleaned up by octadecylsilane (C18) or primary secondary amine (PSA). Instrumental analysis was completed in 16 min using gas chromatography-tandem mass spectrometry (GC-MS/MS). The overall average recoveries in the six kinds of edible mushrooms at three levels (10, 100 and 1000 μg kg−1) ranged from 72.8% to 103.6%. The intraday and interday relative standard deviations (RSD) were lower than 13.0%. The quantification limits were below 5.57 μg kg−1 in different matrices. The results demonstrated that the method is convenient for the quick detection of pyrethroid insecticides in edible mushrooms.
Subject terms: Mass spectrometry, Chemical safety
Introduction
Edible mushrooms are considered as a delicacy with high nutritive value and unique flavor, and they are also recognized as nutraceutical foods1,2. More importantly than all of that, it is accepted as healthy food with a good deal of medicinal functions and important positive health function3. They are more and more popular with consumers and have been regarded as ingredient of gourmet cuisine all over the world. Pleurotus ostreatus (oyster mushroom), Lentinus edodes (shiitake mushroom), Pleurotus eryngii (eryngii mushroom), Agaricus bisporus (crimini mushroom), Flammulina velutiper (enoki mushroom), and Hypsizygus marmoreus (bunashimeji mushroom) are the six of the most cultivated edible mushrooms. They are quite rich in protein, essential amino acids, fiber, chitin, vitamins and other substances4–7. These ingredients increase the value of these edible mushrooms. In China, edible mushroom production reached 7,868,782 ton in 2017. And the mushroom production accounted for 76.8% of the world2. And it is the most important producers and exporters of mushrooms. However, in recent years, the pests and diseases has become very serious with the expansion of cultivation scale of six edible mushrooms8. Sciarid flies and Cecid are the most important pests in mushroom throughout the world9. It was reported that these pests have caused significant economic losses in the mushroom industry8. Therefore, many insecticides were used on mushrooms to control these pests which can boost yields and reduce the economic losses. So, detailed investigations on pesticide residues in mushrooms are very important to reduce the use of pesticides and ensure food safety.
Many types of synthetic insecticides are frequently used to control pests in mushroom cultivation throughout the world10–12. Because pyrethroids has high level of effectiveness, broad spectrum of effects and low toxicity, it has been widely used in the production all over the world13,14. In 2015, pyrethroids was among the most important classes of insecticides in crop, and it accounted for 38% of the world insecticide market12. Therefore, it is not surprised that pyrethroid residues are frequently detected in different vegetables, fruits, soil and other matrices worldwide15. For example, Ding et al. reported that the highest concentration of pyrethroid residues in vegetables in Zhejiang province reached 330 μg kg−116. To prevent and control Sciarid and Cecid in the process of mushroom cultivation, pyrethroids are frequently used on mushrooms to boost yields. Therefore, determination of pyrethroid residues in mushrooms is important for food safety and normal foreign trade.
As far as we know, many analytical methods have been reported for the determination of pyrethroids in various matrices. Due to co-extraction of highly complex components, such as protein, sterols, essential amino acids, and polysaccharide, extracting pyrethroids residues from edible mushrooms is difficult2. In the extract, these components seriously interfere with the determination of the pyrethroids. Therefore, pretreatment technology is very important in the detection of pyrethroids residues in edible mushrooms17. Usually, a solid-liquid extraction followed by purification is a preliminary sample preparation for the determination of pesticide residues in edible mushrooms. The purification techniques, including solid-phase extraction (SPE), gel permeation chromatography (GPC), and matrix solid-phase dispersion, are the most commonly used techniques for pretreatment procedures18–20. However, these sample preparation methods are complicated and use larger amounts of organic solvents21,22. In recent years, the QuEChERS methodology has been develpoed as a very popular method to determine pesticide residues in all kinds of food matrices23–29. And there are some papers that applied QuEChERS for the extraction of pesticides from mushrooms and determination of residue used GC, GC-MS/MS30,31, or LC-MS/MS10,11. However, simultaneous determination of pyrethroid residues in mushrooms by GC-MS/MS has not been reported. Moreover, GC-MS/MS is becoming more and more popular in routine pesticide residue analysis because of fewer co-matrix effects resulting in sensitive identification and the reagents costing less compared with HPLC/UPLC-MS/MS32.
Therefore, the aim of this paper is focused on the investigation of a rapid and effective extraction procedure using a modified QuEChERS method for simultaneously analyzing pyrethroids in various edible mushrooms (oyster mushroom, shiitake mushroom, eryngii mushroom, crimini mushroom, enoki mushroom and bunashimeji mushroom). Various extraction solvents and cleanup sorbents were studied for optimizing the pretreatment method to obtain higher recoveries. The developed method was successfully used to analyze authentic samples.
Results and Discussion
Optimization of GC-MS/MS parameters
The pyrethroid insecticides involved were monitored in the full scanning mode in the range m/z 50–600 to describe its scanning mass spectrogram and retention time. Then, the multiple reaction monitoring (MRM) transitions were optimized. The purpose of selecting precursor ions was to achieve a compromise between selectivity (the highest m/z ion is preferred) and sensitivity (the highest abundance ion). The method was divided into as many time segments as possible to achieve the maximum signal for each compound. The MS/MS transition was selected according the highest response for the each target compound. The run time of these pesticides were completed in 16 min. All the parameters for precursor ions, product ion, corresponding collision energies, and other optimal conditions were determined and shown in Table 1.
Table 1.
Details of the MS/MS parameters for analysis of the compounds.
| Compounds | Molecular formula | Molecular weight | Precursor ion (m/z) | Product ion (m/z) | Q/q a | Collision energy (v) | Dwell time (s) | Retention time (min) |
|---|---|---|---|---|---|---|---|---|
| Bifenthrin | C23H22ClF3O2 | 422.9 | 181.2 | 166.2 | Q | 10 | 24 | 11.54 |
| 181.2 | 165.2 | q | 20 | 24 | ||||
| Fenpropathrin | C22H23NO3 | 349.4 | 207.9 | 181.0 | Q | 5 | 24 | 11.63 |
| 264.9 | 210.0 | q | 10 | 24 | ||||
| Cyhalothrin | C23H19ClF3NO3 | 449.9 | 197.0 | 141.0 | Q | 10 | 24 | 12.01, 12.13 |
| 197.0 | 161.0 | q | 5 | 24 | ||||
| Permethrin | C21H20Cl2O3 | 391.3 | 183.1 | 168.1 | Q | 15 | 18 | 12.66, 12.74 |
| 183.1 | 153.0 | q | 10 | 18 | ||||
| Cyfluthrin | C22H18Cl2FNO3 | 434.3 | 226.0 | 206.0 | Q | 18 | 15 | 13.05, 13.11, 13.18 |
| 198.9 | 170.1 | q | 18 | 25 | ||||
| Cypermethrin | C22H19Cl2NO3 | 416.3 | 163.0 | 91.0 | Q | 18 | 10 | 13.29, 13.36, 13.44 |
| 163.0 | 127.0 | q | 18 | 5 | ||||
| Flucythrinate | C26H23F2NO4 | 451.5 | 156.9 | 107.1 | Q | 18 | 15 | 13.39, 13.53 |
| 198.9 | 157.0 | q | 18 | 15 | ||||
| Tau-fluvalinate | C26H22ClF3N2O3 | 502.9 | 250.0 | 55.0 | Q | 37 | 40 | 14.19, 14.24 |
| 181.0 | 152.0 | q | 37 | 40 | ||||
| Fenvalerate | C25H22ClNO3 | 419.9 | 167.0 | 125.1 | Q | 37 | 5 | 14.02, 14.20 |
| 224.9 | 119.0 | q | 37 | 15 | ||||
| Deltamethrin | C22H19Br2NO3 | 505.2 | 252.9 | 93.0 | Q | 37 | 15 | 14.73 |
| 250.7 | 172.0 | q | 37 | 5 |
a Q is quantification ion transition and q is confirmation ion transition.
Optimization of extraction solvents and clean up sorbents
The choice of suitable solvent and sorbent has huge influence on the recoveries. Therefore, the solvents and sorbents need to be optimized. Firstly, the extraction solvent was studied. Acetonitrile was frequently used for pesticide multi-residue analysis with advantages including, less co-extracted matrix components, higher recoveries, etc.2,24,27,33. Meanwhile, pyrethroid insecticides have high solubility in n-hexane at 20 °C. Therefore, the recoveries of acetonitrile and n-hexane as extraction solvents were compared. As shown in Fig. 1, taking eryngii mushroom as an example, the recoveries of the ten pyrethroid insecticides at a spiked level of 100 μg kg−1 using acetonitrile as the extraction solvent was significantly higher than that of n-hexane. Consequently, acetonitrile was selected as the extraction solvents in further study.
Figure 1.
Effect of acetonitrile and n-hexane as extraction solvents for the target compounds in eryngii mushroom at 100 μg kg−1 level (n = 3).
To achieve a satisfactory effect, we evaluated the different types of sorbents at a spiked level of 100 μg kg−1. Test A was carried out using 50 mg PSA + 150 mg MgSO4, test B using 20 mg PSA + 30 mg C18 + 150 mg MgSO4, test C using 50 mg C18 + 150 mg MgSO4, and test D using an Enhanced Matrix Removal-Lipid (EMR-Lipid). Meanwhile, the four matrix standards were prepared from each dispersive solid phase extraction (dSPE) cleanup technique so that each (C18, PSA or PSA + C18, etc.) could be tested against standards with the same composition of matrix compounds. For the dSPE, PSA is mainly applied to adsorb various polar matrix components from non-polar samples like organic acids and pigments. Conversely, C18 is mainly used to remove non-polar and medium-polar compounds from the polar samples2,33,34. Particularly, the dSPE EMR is applied to remove the lipid35. As shown in Fig. 2, the recovery and RSD were both satisfied when the four different types of sorbents were used in the oyster mushroom. Nevertheless, when C as sorbent was used in shiitake mushroom, the recoveries of ten target compounds was satisfactory. Meanwhile, A as sorbent was used in bunashimeji mushroom, the recoveries was satisfactory. For the crimini mushroom and enoki mushroom, the recovery and RSD were both satisfied when sorbent A, sorbent B and sorbent D were used. PSA is relatively expensive than C18. Therefore, considering the efficacy and cost of each sorbent, 20 mg PSA + 30 mg C18 + 150 mg MgSO4 was ultimately selected as sorbent for oyster mushroom and eryngii mushroom extracts. 50 mg PSA + 150 mg MgSO4 was used as the sorbent for crimini mushroom, enoki mushroom and bunashimeji mushroom extracts, while for the shiitake mushroom requires used 50 mg C18 + 150 mg MgSO4 purification.
Figure 2.
Effects of different sorbents for the targeted compounds in different matrix at 100 μg kg−1 level (n = 5).
Matrix effects
The ionization of some pesticides may be significantly affected by the presence of substances, which are derived from samples36. In 1993, matrix effect was first explained by Erney and co-workers, and their study suggested that the response of one organic base decreased as the concentration of other bases increased37. The matrix effects can greatly affect the reproducibility and accuracy of the method. Thus, matrix effect was studied in edible mushrooms. Generally speaking, the matrix effect was ignored if the value was between −10% and 10%; the matrix effect was defined as suppression if the value was lower than −10%; the matrix effect was defined as enhancement if the value was higher than 10%23,24. As shown in Table 2, the matrix effects obviously enhance the response of the instrument in all matrices. And the slope ratios of matrix/n-hexane were in the range of 1.47–2.77. In order to eliminate the matrix effect and determine more accurate results for each target compound concentration in all samples, the matrix-matched calibration curves were selected to calibrate the GC-MS/MS system.
Table 2.
Comparison of matrix-matched calibration and solvent calibration at 10–1000 μg kg−1.
| Compound | Matrix | Regression equation | R2 | Matrix effect (%) | LOD (μg kg−1) |
LOQ (μg kg−1) |
|---|---|---|---|---|---|---|
| Bifenthrin | n-Hexane | y = 917.43×−1669.74 | 0.9992 | — | — | — |
| Oyster mushroom | y = 1378.65×+11014.79 | 0.9998 | 50.27 | 0.037 | 0.122 | |
| Shiitake mushroom | y = 1406.06×+4712.20 | 0.9995 | 53.26 | 0.071 | 0.237 | |
| Eryngii mushroom | y = 1410.36×−963.07 | 0.9992 | 53.73 | 0.021 | 0.069 | |
| Crimini mushroom | y = 1350.62×+6803.68 | 0.9994 | 47.22 | 0.016 | 0.054 | |
| Enoki mushroom | y = 1366.83 + 17846.90 | 0.9989 | 48.98 | 0.038 | 0.126 | |
| Bunashimeji mushroom | y = 1419.98 + 5624.00 | 0.9999 | 54.78 | 0.025 | 0.083 | |
| Fenpropathrin | n-Hexane | y = 69.32×−1602.22 | 0.9976 | — | — | — |
| Oyster mushroom | y = 112.28×+156.06 | 0.9999 | 61.97 | 0.148 | 0.492 | |
| Shiitake mushroom | y = 114.69×−108.54 | 0.9994 | 65.45 | 0.161 | 0.537 | |
| Eryngii mushroom | y = 113.88×−558.57 | 0.9991 | 64.28 | 0.034 | 0.112 | |
| Crimini mushroom | y = 107.86×+21.11 | 0.9995 | 55.60 | 0.105 | 0.351 | |
| Enoki mushroom | y = 107.80×+871.59 | 0.9993 | 55.51 | 0.116 | 0.385 | |
| Bunashimeji mushroom | y = 111.61×−255.32 | 0.9999 | 61.01 | 0.754 | 2.515 | |
| Cyhalothrin | n-Hexane | y = 94.09×−2757.26 | 0.9952 | — | — | — |
| Oyster mushroom | y = 185.33×−1579.27 | 0.9998 | 96.97 | 1.211 | 4.036 | |
| Shiitake mushroom | y = 203.46×−1374.18 | 0.9990 | 116.24 | 0.304 | 1.014 | |
| Eryngii mushroom | y = 195.85×−2845.42 | 0.9982 | 108.15 | 0.812 | 2.705 | |
| Crimini mushroom | y = 178.54×−1265.32 | 0.9997 | 89.75 | 0.138 | 0.458 | |
| Enoki mushroom | y = 181.44×−661.70 | 1.0000 | 92.84 | 0.230 | 0.767 | |
| Bunashimeji mushroom | y = 176.70×−1785.85 | 0.9996 | 87.80 | 0.237 | 0.791 | |
| Permethrin | n-Hexane | y = 229.92×−1715.55 | 0.9990 | — | — | — |
| Oyster mushroom | y = 380.94×+9262.22 | 0.9992 | 65.68 | 0.059 | 0.196 | |
| Shiitake mushroom | y = 398.28×+11871.62 | 0.9984 | 73.23 | 0.032 | 0.108 | |
| Eryngii mushroom | y = 382.27×+2916.55 | 0.9993 | 66.26 | 0.026 | 0.086 | |
| Crimini mushroom | y = 366.04×+8864.70 | 0.9991 | 59.20 | 0.015 | 0.051 | |
| Enoki mushroom | y = 367.54×+8021.24 | 0.9989 | 59.86 | 0.036 | 0.119 | |
| Bunashimeji mushroom | y = 384.23×+7303.04 | 0.9995 | 67.11 | 0.025 | 0.083 | |
| Cyfluthrin | n-Hexane | y = 93.91×−2395.75 | 0.9985 | — | — | — |
| Oyster mushroom | y = 234.30×−3149.71 | 0.9995 | 149.49 | 0.488 | 1.625 | |
| Shiitake mushroom | y = 249.29×−2914.76 | 0.9987 | 165.46 | 1.163 | 3.876 | |
| Eryngii mushroom | y = 230.07×−4354.54 | 0.9976 | 144.99 | 0.127 | 0.424 | |
| Crimini mushroom | y = 212.24×−3468.49 | 0.9989 | 126.00 | 0.103 | 0.344 | |
| Enoki mushroom | y = 205.24×−2701.42 | 0.9994 | 118.55 | 0.363 | 1.211 | |
| Bunashimeji mushroom | y = 214.95×−3724.08 | 0.9983 | 128.89 | 1.073 | 3.576 | |
| Cypermethrin | n-Hexane | y = 204.64×−7437.40 | 0.9936 | — | — | — |
| Oyster mushroom | y = 475.19×+1202.65 | 0.9998 | 132.21 | 0.065 | 0.218 | |
| Shiitake mushroom | y = 506.74×+13.76 | 0.9989 | 147.63 | 0.059 | 0.195 | |
| Eryngii mushroom | y = 475.26×−1499.63 | 0.9983 | 132.24 | 0.126 | 0.419 | |
| Crimini mushroom | y = 443.91×+2479.19 | 0.9993 | 116.92 | 1.259 | 4.198 | |
| Enoki mushroom | y = 430.10×+1144.36 | 0.9998 | 110.17 | 0.723 | 2.411 | |
| Bunashimeji mushroom | y = 451.72×+740.57 | 0.9989 | 120.74 | 1.221 | 4.068 | |
| Flucythrinate | n-Hexane | y = 388.40×−12880.95 | 0.9945 | — | — | — |
| Oyster mushroom | y = 1030.38×−7947.70 | 0.9999 | 165.29 | 0.451 | 1.503 | |
| Shiitake mushroom | y = 1077.43×−8247.59 | 0.9991 | 177.40 | 0.222 | 0.739 | |
| Eryngii mushroom | y = 1020.13×−9961.48 | 0.9988 | 162.65 | 0.869 | 2.896 | |
| Crimini mushroom | y = 954.05×−8132.86 | 0.9995 | 145.64 | 0.070 | 0.233 | |
| Enoki mushroom | y = 940.39×−3366.13 | 0.9999 | 142.12 | 0.149 | 0.496 | |
| Bunashimeji mushroom | y = 970.90×−10710.4 | 0.9994 | 149.97 | 0.122 | 0.407 | |
| Tau-fluvalinate | n-Hexane | y = 23.03×−268.86 | 0.9987 | — | — | — |
| Oyster mushroom | y = 48.05×−1026.10 | 0.9964 | 108.64 | 0.468 | 1.560 | |
| Shiitake mushroom | y = 54.90×−847.89 | 0.9961 | 138.38 | 0.355 | 1.183 | |
| Eryngii mushroom | y = 49.10×−1231.91 | 0.9955 | 113.20 | 1.184 | 3.947 | |
| Crimini mushroom | y = 43.50×−683.67 | 0.9969 | 88.88 | 0.604 | 2.015 | |
| Enoki mushroom | y = 40.51×−732.66 | 0.9975 | 75.90 | 0.787 | 2.622 | |
| Bunashimeji mushroom | y = 42.48×−867.74 | 0.9951 | 84.46 | 0.673 | 2.242 | |
| Fenvalerate | n-Hexane | y = 116.97×−5266.69 | 0.9906 | — | — | — |
| Oyster mushroom | y = 298.44×−5894.21 | 0.9991 | 155.14 | 0.669 | 2.229 | |
| Shiitake mushroom | y = 319.06×−5407.40 | 0.9984 | 172.77 | 1.669 | 5.565 | |
| Eryngii mushroom | y = 298.29×−6626.48 | 0.9975 | 155.01 | 1.374 | 4.580 | |
| Crimini mushroom | y = 277.95×−5612.92 | 0.9987 | 137.63 | 1.048 | 3.492 | |
| Enoki mushroom | y = 270.36×−4366.27 | 0.9995 | 131.14 | 0.750 | 2.499 | |
| Bunashimeji mushroom | y = 277.19×−5915.89 | 0.9984 | 136.98 | 0.219 | 0.730 | |
| Deltamethrin | n-Hexane | y = 31.82×−984.06 | 0.9953 | — | — | — |
| Oyster mushroom | y = 86.78×−2872.02 | 0.9958 | 172.72 | 1.210 | 4.032 | |
| Shiitake mushroom | y = 78.89×−2031.72 | 0.9967 | 147.93 | 0.071 | 0.238 | |
| Eryngii mushroom | y = 85.89×−1656.28 | 0.9976 | 169.92 | 1.312 | 4.373 | |
| Crimini mushroom | y = 75.92×−534.92 | 0.9962 | 138.59 | 0.035 | 0.118 | |
| Enoki mushroom | y = 72.69×−1603.40 | 0.9953 | 128.44 | 0.076 | 0.252 | |
| Bunashimeji mushroom | y = 70.21×−992.51 | 0.9989 | 120.65 | 0.093 | 0.310 |
Matrix effect (%) = ((slope matrix/slope solvent) − 1) ×100.
Linearity, LOD, and LOQ
The calibration curves in different edible mushrooms matrices were shown in Table 2. The linearity for each target compound in each edible mushroom matrix was satisfactory (R2 ≥ 0.9901 in all cases). The LODs of ten pyrethroid insecticides ranged from 0.015 to 1.67 μg kg−1, and LOQs ranged from 0.051 to 5.57 μg kg−1 in original samples. These values were similar to the values of other pesitcides reported in the literature31,38,39. And the LOQs for ten target compounds were much lower than the maximum residue limit (MRLs) (100–1000 μg kg−1) recommended by the EU, Japan, USA and China.
Precision and accuracy
A recovery assay was performed to validate the performance of the proposed method. The blank samples of different matrices were spiked at three different concentrations (10, 100 and 1000 μg kg−1) and then determining them in quintuplicate. The method’s precision was expressed as the RSD. As indicated in Table 3, mean recoveries of ten target compounds were in the acceptable ranges of 80.8–97.7% with RSDr of 1.0–8.4%, 81.5–103.6% with RSDr of 1.8–8.4%, 72.8–97.5% with RSDr of 1.4–7.0%, 81.4–102.2% with RSDr of 2.4–8.9%, 75.6–100.0% with RSDr of 2.4–9.0%, 75.0–103.3% with RSDr of 1.0–8.4% for oyster mushroom, shiitake mushroom, eryngii mushroom, crimini mushroom, enoki mushroom and bunashimeji mushroom, respectively. In general, the mean recoveries of ten target compounds were 72.8–103.6% in all matrices, and the RSDr (n = 5) and RSDR (n = 15) values ranged from 1.0% to 9.0% and 3.1% to 13.0%, respectively. For the statistical analysis, one-way analysis of variance (ANOVA) at 95% confidence limits was used to compare the interday and intraday assay recoveries, and there were no significant differences between the interday and intraday assays. Therefore, the results indicated that the extract method and GC-MS/MS analysis can obtain a satisfactory precision and accuracy for residue analysis of these ten pyrethroid insecticides in edible mushrooms.
Table 3.
Recoveries (n = 15, %), RSDra and RSDRb (%) for target compounds from different matrices at three spiked levels.
| Oyster mushroom | Shiitake mushroom | Eryngii mushroom | Crimini mushroom | Enoki mushroom | Bunashimeji mushroom | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.01 | 0.1 | 1 | 0.01 | 0.1 | 1 | 0.01 | 0.1 | 1 | 0.01 | 0.1 | 1 | 0.01 | 0.1 | 1 | 0.01 | 0.1 | 1 | ||
| Bifenthrin | Recovery | 89.6 | 86.9 | 92.1 | 87.3 | 83.2 | 86.0 | 75.9 | 74.8 | 78.6 | 97.1 | 85.7 | 81.4 | 87.5 | 75.6 | 81.9 | 88.6 | 75.7 | 80.6 |
| RSDra | 7.3 | 3.3 | 5.5 | 8.1 | 5.8 | 2.7 | 3.7 | 3.1 | 3.4 | 2.4 | 4.6 | 7.9 | 3.6 | 5.0 | 4.9 | 1.7 | 3.9 | 3.6 | |
| RSDRb | 7.5 | 5.5 | 8.5 | 6.6 | 4.5 | 5.9 | 4.3 | 4.1 | 3.6 | 6.0 | 8.4 | 8.4 | 6.9 | 7.4 | 6.8 | 3.7 | 7.3 | 5.4 | |
| Fenpropathrin | Recovery | 89.0 | 91.9 | 87.6 | 88.8 | 84.2 | 84.9 | 76.8 | 74.9 | 87.0 | 102.0 | 86.1 | 84.9 | 79.7 | 78.7 | 83.7 | 91.8 | 75.8 | 82.7 |
| RSDra | 6.6 | 3.0 | 3.4 | 4.2 | 5.4 | 2.8 | 3.5 | 2.9 | 3.8 | 2.5 | 7.5 | 8.9 | 7.6 | 6.6 | 5.7 | 1.8 | 2.2 | 4.4 | |
| RSDRb | 10.5 | 6.1 | 4.7 | 4.3 | 6.7 | 5.4 | 3.4 | 4.1 | 3.5 | 8.1 | 9.1 | 6.3 | 7.1 | 6.1 | 7.2 | 3.6 | 4.4 | 13.0 | |
| Cyhalothrin | Recovery | 97.7 | 94.5 | 90.1 | 89.6 | 86.0 | 87.6 | 74.9 | 72.8 | 88.5 | 96.3 | 84.7 | 90.7 | 91.7 | 74.8 | 87.6 | 97.9 | 78.5 | 84.8 |
| RSDra | 1.0 | 5.0 | 8.4 | 5.0 | 3.4 | 2.5 | 3.8 | 2.6 | 2.0 | 4.9 | 4.2 | 7.4 | 5.0 | 4.3 | 5.5 | 5.5 | 2.9 | 5.9 | |
| RSDRb | 4.7 | 7.9 | 7.5 | 3.8 | 7.1 | 5.3 | 4.2 | 3.1 | 6.4 | 5.3 | 7.0 | 8.1 | 6.1 | 5.6 | 6.5 | 7.1 | 5.6 | 5.5 | |
| Permethrin | Recovery | 91.9 | 84.4 | 80.8 | 91.0 | 85.3 | 83.2 | 97.2 | 80.8 | 87.7 | 89.7 | 85.9 | 83.5 | 92.6 | 78.5 | 84.4 | 98.8 | 82.1 | 87.2 |
| RSDra | 4.2 | 3.2 | 8.0 | 3.8 | 5.7 | 4.1 | 3.8 | 4.6 | 4.7 | 3.6 | 3.0 | 6.9 | 5.2 | 6.8 | 5.6 | 2.8 | 3.6 | 4.1 | |
| RSDRb | 6.3 | 5.7 | 7.3 | 4.7 | 5.7 | 6.2 | 5.0 | 5.2 | 5.4 | 8.2 | 6.3 | 7.1 | 7.2 | 5.6 | 7.5 | 5.6 | 7.3 | 5.8 | |
| Cyfluthrin | Recovery | 96.9 | 95.6 | 90.1 | 87.0 | 83.5 | 88.7 | 74.0 | 78.4 | 77.8 | 97.6 | 82.6 | 83.1 | 86.2 | 81.0 | 86.6 | 94.5 | 82.2 | 83.9 |
| RSDra | 3.6 | 4.1 | 7.9 | 4.7 | 5.0 | 3.7 | 2.3 | 1.9 | 4.5 | 5.0 | 5.5 | 7.8 | 9.0 | 6.7 | 6.9 | 4.1 | 3.0 | 8.0 | |
| RSDRb | 4.4 | 4.3 | 6.2 | 7.6 | 5.7 | 6.2 | 3.3 | 4.0 | 7.3 | 6.4 | 9.2 | 8.5 | 8.1 | 7.4 | 6.7 | 5.0 | 6.3 | 9.4 | |
| Cypermethrin | Recovery | 95.6 | 95.5 | 89.0 | 103.6 | 92.5 | 90.7 | 97.5 | 75.8 | 80.8 | 93.5 | 88.5 | 88.3 | 100.0 | 89.1 | 83.9 | 103.3 | 80.0 | 80.8 |
| RSDra | 5.9 | 5.5 | 8.4 | 1.8 | 8.7 | 6.0 | 1.4 | 4.3 | 4.6 | 4.0 | 4.5 | 8.3 | 2.5 | 3.4 | 6.0 | 2.8 | 2.4 | 6.4 | |
| RSDRb | 4.7 | 6.0 | 7.6 | 4.3 | 6.0 | 6.8 | 6.0 | 7.1 | 6.5 | 8.3 | 6.7 | 6.3 | 5.3 | 5.0 | 3.5 | 3.5 | 5.9 | 9.0 | |
| Flucythrinate | Recovery | 90.3 | 84.9 | 86.1 | 85.2 | 81.5 | 88.6 | 77.6 | 76.1 | 85.4 | 95.6 | 88.3 | 85.6 | 82.3 | 83.6 | 86.3 | 94.4 | 77.7 | 85.9 |
| RSDra | 2.6 | 5.8 | 4.3 | 3.9 | 5.4 | 3.8 | 6.3 | 3.8 | 4.2 | 2.4 | 4.3 | 5.9 | 5.6 | 2.4 | 5.9 | 5.2 | 4.6 | 6.2 | |
| RSDRb | 3.4 | 10.5 | 8.6 | 5.8 | 7.6 | 4.4 | 7.3 | 5.9 | 8.7 | 6.7 | 5.0 | 7.0 | 7.4 | 4.1 | 5.8 | 7.2 | 6.6 | 9.3 | |
| Tau-fluvalinate | Recovery | 94.4 | 94.0 | 92.4 | 93.8 | 87.9 | 101.2 | 79.9 | 83.9 | 79.3 | 102.2 | 82.8 | 90.2 | 89.9 | 81.9 | 97.8 | 93.6 | 77.3 | 83.9 |
| RSDra | 3.6 | 5.8 | 4.9 | 4.9 | 4.4 | 2.8 | 4.8 | 4.1 | 5.7 | 2.6 | 5.1 | 7.0 | 8.1 | 6.0 | 6.8 | 3.4 | 4.1 | 7.0 | |
| RSDRb | 4.7 | 6.5 | 4.3 | 5.4 | 6.9 | 5.0 | 9.1 | 10.4 | 3.8 | 4.5 | 5.6 | 7.0 | 5.8 | 7.4 | 7.2 | 7.7 | 4.9 | 10.2 | |
| Fenvalerate | Recovery | 92.9 | 88.4 | 87.7 | 90.5 | 84.5 | 103.6 | 75.9 | 81.9 | 91.7 | 98.3 | 82.9 | 101.4 | 79.0 | 82.4 | 94.7 | 90.4 | 81.4 | 91.4 |
| RSDra | 2.3 | 4.5 | 4.7 | 8.3 | 3.7 | 2.9 | 4.7 | 5.0 | 5.4 | 5.1 | 5.5 | 6.0 | 6.5 | 6.8 | 4.0 | 4.8 | 6.1 | 2.5 | |
| RSDRb | 5.7 | 7.5 | 6.7 | 7.2 | 5.2 | 5.7 | 5.5 | 8.5 | 5.7 | 5.2 | 5.4 | 5.9 | 6.7 | 6.1 | 8.0 | 6.2 | 7.2 | 6.0 | |
| Deltamethrin | Recovery | 91.3 | 88.4 | 77.6 | 97.9 | 85.8 | 92.4 | 91.6 | 81.2 | 76.8 | 100.5 | 89.2 | 83.6 | 96.5 | 91.6 | 81.8 | 91.3 | 75.0 | 83.6 |
| RSDra | 6.5 | 7.7 | 4.9 | 4.4 | 5.4 | 3.1 | 7.0 | 6.9 | 7.5 | 3.5 | 3.2 | 3.7 | 2.4 | 5.4 | 7.1 | 2.5 | 2.3 | 4.8 | |
| RSDRb | 4.6 | 7.6 | 6.0 | 4.8 | 6.6 | 5.5 | 4.6 | 7.0 | 8.1 | 4.2 | 4.8 | 7.1 | 5.9 | 8.5 | 12.4 | 8.6 | 7.5 | 8.2 | |
The recovery is the mean recovery.
aIntra-day (n = 5).
bInter-day (n = 15).
Application to real samples
The proposed method was applied to monitor trace levels of each target compounds in real samples to demonstrate the effectiveness and applicability. These samples were purchased from markets in Anhui Province (China). A total of 90 samples (20 oyster mushroom samples, 20 shiitake mushroom samples, 10 eryngii mushroom samples, 20 crimini mushroom samples, 10 enoki mushroom samples, and 10 bunashimeji mushroom samples) were analyzed. As shown in Table 4, only two positive oyster mushroom samples and three positive crimini mushroom samples were detected containing cypermethrin in the range of 11–43 μg kg−1. However, the presence of cypermethrin doesn’t pose a threat to the consumer, because they are below the MRLs settled by EU (50 μg kg−1 for oyster mushroom and crimini mushroom), China (500 μg kg−1 for oyster mushroom and crimini mushroom) and Japan (50 μg kg−1 for crimini mushroom and 500 μg kg−1 for oyster mushroom). But the residual concentration of cypermethrin in some crimini mushroom samples is very close to MRL settled by EU and Japan. Therefore, detection of cypermethrin residues in mushrooms should be strengthened. However, ten pyrethroid insecticides were not found in most of tested samples.
Table 4.
Concentration levels of ten pyrethroid insecticides in edible mushroom samples from market in Anhui Province.
| Samples | Number of samples | Positive sample ratioa | Concentration (μg kg−1) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Bifenthrin | Fenpropathrin | Cyhalothrin | Permethrin | Cyfluthrin | Cypermethrin | Flucythrinate | Tau-fluvalinate | Fenvalerate | Deltamethrin | |||
| Oyster mushroom | 20 | 2(10%) | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | 24/43b | <LOQ | <LOQ | <LOQ | <LOQ |
| Shiitake mushroom | 20 | 0(0) | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ |
| Eryngii mushroom | 10 | 0(0) | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ |
| Crimini mushroom | 20 | 3(15%) | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | 11/16/35b | <LOQ | <LOQ | <LOQ | <LOQ |
| Enoki mushroom | 10 | 0(0) | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ |
| Bunashimeji mushroom | 10 | 0(0) | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ | <LOQ |
aNumber of positive sample (positive sample ratio).
bThe result of positive samples.
In conclusion, in the present study, a simple, reliable and highly sensitive residue analytical method for the simultaneous determination of ten pyrethroid insecticides in six edible mushrooms using GC-MS/MS was developed. The results showed satisfactory validation parameters in the field of linearity, lower limits, accuracy, and precision. The LOQs were below MRLs recommended by EU, China and Japan in all mushroom matrices. The method has strong matrix effect, but it was successfully normalized using matrix-matched calibration. Therefore, this method may be a useful technique for monitoring pyrethroid insecticide residues in edible mushroom samples.
Materials and Methods
Reagents and chemicals
Insecticide analytical standards were supplied from the National Institute of Metrology (Beijing, China) and were of more than 98% purity. Chromatography grade acetonitrile and n-hexane were achieved from Honeywell International Inc. (New Jersey, USA). The anhydrous magnesium sulfate (MgSO4) and sodium chloride (NaCl) were bought from Beijing Chemical and Reagent Company (Beijing, China). The sorbents of primary secondary amine (PSA) and octadecylsilane (C18) were bought from Agela Technologies Inc. (Beijing, China), and Agilent Bond Elut dSPE EMR-Lipid was also bought from Agela Technologies Inc.
Stocks solutions (1000 mg L−1) of each insecticide standard were prepared in n-hexane. A mixed stock standard solution of 100 mg L−1 containing bifenthrin, fenpropathrin, cyhalothrin, permethrin, cyfluthrin, cypermethrin, flucythrinate, tau-fluvalinate, fenvalerate, and deltamethyrin was prepared by mixing ten stock solutions in equal volume. Subsequently, several standard solutions (10, 50, 100, 200, 500, and 1000 μg L−1) were prepared from the mixed stock solution by serial dilution with n-hexane. The matrix-matched standard solutions (10, 50, 100, 200, 500, and 1000 μg L−1) were similarly prepared by adding the blank sample extracts (oyster mushroom, shiitake mushroom, eryngii mushroom, crimini mushroom, enoki mushroom and bunashimeji mushroom) to each serially diluted standard solution. For the preparation of matrix-matched standard, the method was that appropriate volumes of work standard solution was firstly dried under nitrogen and then redissolved by 1 mL blank sample extract. All solutions were stored at −20 °C in the dark.
Instruments and chromatographic conditions
All sample analyses used an Agilent intuvo 9000 gas chromatograph coupled with a 7000D triple quadrupole mass spectrometer. Separations were performed using Agilent Technologies Capillary Column HP-5MS phenylmethyl siloxane fused-silica capillary analytical column (30 m length × 0.25 mm i.d. × 0.25 μm film thickness). A helium (purity 99.99%) was employed as carrier gas and the flow rate was 1.0 mL min−1. The temperature of the injection port was 280 °C. The column temperature was initially at 70 °C for 1 min, increased to 120 °C at the rate of 40 °C min−1, and increased to 200 °C at the rate of 30 °C min−1, then increased to 240 °C at the rate of 10 °C min−1, and then increased to 300 °C at the rate of 20 °C min−1, and holding for 3.7 min. A volume of 1 μL was injected in the splitless mode.
The mass spectrometer was performed in electron ionization mode with an ionizing energy of 70 eV. The electron multiplier voltage was 1300 V. The transfer line, manifold and ionization source temperatures were 280, 40 and 250 °C, respectively. A solvent delay was 8 min. The mass spectrometer mode was set at multiple reaction monitoring (MRM) to collect data. The concrete MS/MS parameters for all the analytes listed in Table 1.
Sample preparation
Figure 3 shows the workflow of the sample preparation procedure. For the cleanup procedure, the 20 mg PSA and 30 mg C18 were selected to clean up the oyster mushroom and eryngii mushroom; the 50 mg PSA was used to purify the crimini mushroom, enoki mushroom and bunashimeji mushroom, and 50 mg C18 was used to clean up the shiitake mushroom.
Figure 3.
Workflow of sample preparation.
For the Agilent Bond Elut EMR-Lipid clean up, the extract procedure is the same as above. 5 mL Milli-Q water was added into EMR-Lipid tube to activate the sorbent. Then, 5 mL upper layer (acetonitrile) was added into the tube. The tube was vortexed for 5 min and then centrifuged for 5 min at relative centrifugal force (RCF) 3913 × g. Subsequently, 5 mL upper layer was transferred into the EMR-Polish tube that containing 2 g salt (1:4 NaCl: MgSO4). The tube was vortexed for 5 min and centrifuged for 3 min at RCF 2811 × g. Then, 1 mL upper layer (acetonitrile) was reduced to dryness under a gentle stream of nitrogen at room temperature. The residue was reconstituted in 1 mL n-hexane and was filtered with 0.22-μm filters for GC-MS/MS analysis.
Method validation
The developed method was validated by fortifying blank mushroom samples at three different levels (10, 100, and 1000 μg kg−1). Recovery assays were performed to determine the accuracy and precision of the method. For determination of the accuracy, five replicates of each fortification level were prepared on three different days (n = 15 in total). However, the intra-day and inter-day relative standard deviation (RSD) were also investigated as the method precision. The linear regression equations of each target compound were achieved from the peak area ratios plotted against its respective concentrations (10–1000 μg kg−1). The linearity was presented as correlation coefficient (R2). The limit of detection (LOD) for each target compound was defined as the minimum spiking level that produced a chromatogram peak with signal-to-noise (peak to peak) ratio of 3, and the limit of quantification (LOQ) was defined as a signal-to-noise ratio of 1023.
Acknowledgements
This work was supported by the Agricultural Science and Technology Innovation Program (Grant CAAS-ASTIP-2019-ZFRI-10), the Central Public-interest Scientific Institution Basal Research Fund (No.1610192020106), and the quality and safety risk assessment for agro-products of China (Grant GJFP 2019041).
Author contributions
Fajun Tian wrote the main manuscript text and conducted the experiments. Chengkui Qiao provided some suggestion for revision and corrected the grammatical mistakes. Jing Luo helped process the samples. Linlin Guo reviewed the manuscript. Tao Pang reviewed the manuscript. Rongli Pang reviewed the manuscript. Jun Li reviewed the manuscript. Caixia Wang reviewed the manuscript. Ruiping Wang reviewed the manuscript. Hanzhong Xie coordinated the study and helped draft the manuscript.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Ergonul, P. G., Akata, I., Kalyoncu, F. & Ergonul, B. Fatty Acid Compositions of Six Wild Edible Mushroom Species. Scientific World Journal, 4, 10.1155/2013/163964 (2013). [DOI] [PMC free article] [PubMed]
- 2.Lu Z, et al. Simultaneous Determination of Five Neonicotinoid Insecticides in Edible Fungi Using Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS) Food Anal. Methods. 2018;11:1086–1094. doi: 10.1007/s12161-017-1080-2. [DOI] [Google Scholar]
- 3.Kalač P. A review of chemical composition and nutritional value of wild‐growing and cultivated mushrooms. J. Sci. Food Agric. 2013;93:209–218. doi: 10.1002/jsfa.5960. [DOI] [PubMed] [Google Scholar]
- 4.Valverde, M. E., Hernandez-Perez, T. & Paredes-Lopez, O. Edible mushrooms: improving human health and promoting quality life. International Journal of Microbiology2015, 376387-Article ID 376387 (2015). [DOI] [PMC free article] [PubMed]
- 5.Heleno SA, Barros L, Sousa MJ, Martins A, Ferreira I. Tocopherols composition of Portuguese wild mushrooms with antioxidant capacity. Food Chem. 2010;119:1443–1450. doi: 10.1016/j.foodchem.2009.09.025. [DOI] [Google Scholar]
- 6.Mattila P, et al. Contents of vitamins, mineral elements, sand some phenolic compounds in cultivated mushrooms. J. Agric. Food. Chem. 2001;49:2343–2348. doi: 10.1021/jf001525d. [DOI] [PubMed] [Google Scholar]
- 7.Wang JL, et al. A polysaccharide from Lentinus edodes inhibits human colon cancer cell proliferation and suppresses tumor growth in athymic nude mice. Oncotarget. 2017;8:610–623. doi: 10.18632/oncotarget.13481. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Lewandowski M, Sznyk A, Bednarek A. Biology and morphometry of Lycoriella ingenua(Diptera: Sciaridae) Biological Letters. 2004;41:41–50. [Google Scholar]
- 9.Binns E. Sciarids as migrants. Mushroom J. 1981;108:415–423. [Google Scholar]
- 10.Du P, et al. Rapid residue analysis of pyriproxyfen, avermectins and diflubenzuron in mushrooms by ultra-performance liquid chromatography coupled with tandem mass spectrometry. Anal. Methods. 2013;5:6741–6747. doi: 10.1039/c3ay41074a. [DOI] [Google Scholar]
- 11.Tian FJ, et al. Simultaneous Determination of Phoxim, Chlorpyrifos, and Pyridaben Residues in Edible Mushrooms by High-Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry. Food Anal. Methods. 2016;9:2917–2924. doi: 10.1007/s12161-016-0490-x. [DOI] [Google Scholar]
- 12.Li HZ, Cheng F, Wei YL, Lydy MJ, You J. Global occurrence of pyrethroid insecticides in sediment and the associated toxicological effects on benthic invertebrates: An overview. J. Hazard. Mater. 2017;324:258–271. doi: 10.1016/j.jhazmat.2016.10.056. [DOI] [PubMed] [Google Scholar]
- 13.Weston DP, Holmes RW, You J, Lydy MJ. Aquatic toxicity due to residential use of pyrethroid insecticides. Environmental Science &. Technology. 2005;39:9778–9784. doi: 10.1021/es0506354. [DOI] [PubMed] [Google Scholar]
- 14.Spurlock, F. & Lee, M. In Synthetic Pyrethroids Vol. 991 Acs Symposium Series (eds. Gan, J., F. Spurlock, F., Hendley, P. & Weston, D. P.) 3–25 (Amer Chemical Soc, 2008).
- 15.Tang WX, et al. Pyrethroid pesticide residues in the global environment: An overview. Chemosphere. 2018;191:990–1007. doi: 10.1016/j.chemosphere.2017.10.115. [DOI] [PubMed] [Google Scholar]
- 16.Ding, J.-q., Cai, X., Zhong, L.-k., Xie, Y.-j. & Chen, M.-n. Analysis on pesticide residues in vegetables in Zhenhai district of Ningbo [J]. ChineseJournal of Health Laboratory Technology4 (2011).
- 17.Bidari A, Ganjali MR, Norouzi P, Hosseini MRM, Assadi Y. Sample preparation method for the analysis of some organophosphorus pesticides residues in tomato by ultrasound-assisted solvent extraction followed by dispersive liquid-liquid microextraction. Food Chem. 2011;126:1840–1844. doi: 10.1016/j.foodchem.2010.11.142. [DOI] [PubMed] [Google Scholar]
- 18.Pizzutti IR, et al. Method validation for the analysis of 169 pesticides in soya grain, without clean up, by liquid chromatography-tandem mass spectrometry using positive and negative electrospray ionization. J. Chromatogr. A. 2007;1142:123–136. doi: 10.1016/j.chroma.2006.12.030. [DOI] [PubMed] [Google Scholar]
- 19.Venkateswarlu P, Mohan KR, Kumar CR, Seshaiah K. Monitoring of multi-class pesticide residues in fresh grape samples using liquid chromatography with electrospray tandem mass spectrometry. Food Chem. 2007;105:1760–1766. doi: 10.1016/j.foodchem.2007.04.074. [DOI] [Google Scholar]
- 20.Hu YY, Zheng P, He YZ, Sheng GP. Response surface optimization for determination of pesticide multiresidues by matrix solid-phase dispersion and gas chromatography. J. Chromatogr. A. 2005;1098:188–193. doi: 10.1016/j.chroma.2005.09.093. [DOI] [PubMed] [Google Scholar]
- 21.LeDoux M. Analytical methods applied to the determination of pesticide residues in foods of animal origin. A review of the past two decades. J. Chromatogr. A. 2011;1218:1021–1036. doi: 10.1016/j.chroma.2010.12.097. [DOI] [PubMed] [Google Scholar]
- 22.Martins JG, Chavez AA, Waliszewski SM, Cruz AC, Fabila MMG. Extraction and clean-up methods for organochlorine pesticides determination in milk. Chemosphere. 2013;92:233–246. doi: 10.1016/j.chemosphere.2013.04.008. [DOI] [PubMed] [Google Scholar]
- 23.Hu MF, et al. Method Development and Validation of Indaziflam and Its Five Metabolites in Soil, Water, and Fruits by Modified QuEChERS and UHPLC-MS/MS. J. Agric. Food. Chem. 2018;66:10300–10308. doi: 10.1021/acs.jafc.8604186. [DOI] [PubMed] [Google Scholar]
- 24.Tian F, et al. Simultaneous determination of penflufen and one metabolite in vegetables and cereals using a modified quick, easy, cheap, effective, rugged, and safe method and liquid chromatography coupled to tandem mass spectrometry. Food Chem. 2016;213:410–416. doi: 10.1016/j.foodchem.2016.06.117. [DOI] [PubMed] [Google Scholar]
- 25.Song SY, et al. Residue Analysis of 60 Pesticides in Red Swamp Crayfish Using QuEChERS with High-Performance Liquid Chromatography-Tandem Mass Spectrometry. J. Agric. Food. Chem. 2018;66:5031–5038. doi: 10.1021/acs.jafc.7b05339. [DOI] [PubMed] [Google Scholar]
- 26.Kemmerich M, Bernardi G, Prestes OD, Adaime MB, Zanella R. Comprehensive Method Validation for the Determination of 170 Pesticide Residues in Pear Employing Modified QuEChERS Without Clean-Up and Ultra-High Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry. Food Anal. Methods. 2018;11:556–577. doi: 10.1007/s12161-017-1026-8. [DOI] [Google Scholar]
- 27.Faraji M, Noorbakhsh R, Shafieyan H, Ramezani M. Determination of acetamiprid, imidacloprid, and spirotetramat and their relevant metabolites in pistachio using modified QuEChERS combined with liquid chromatography-tandem mass spectrometry. Food Chem. 2018;240:634–641. doi: 10.1016/j.foodchem.2017.08.012. [DOI] [PubMed] [Google Scholar]
- 28.Anastassiades M, Lehotay SJ, Štajnbaher D, Schenck FJ. Fast and easy multiresidue method employing acetonitrile extraction/partitioning and “dispersive solid-phase extraction” for the determination of pesticide residues in produce. J. AOAC Int. 2003;86:412–431. doi: 10.1093/jaoac/86.2.412. [DOI] [PubMed] [Google Scholar]
- 29.Chen X, et al. Enantioseparation and determination of isofenphos-methyl enantiomers in wheat, corn, peanut and soil with supercritical fluid chromatography/tandem mass spectrometric method. J. Chromatogr. B. 2016;1015:13–21. doi: 10.1016/j.jchromb.2016.02.003. [DOI] [PubMed] [Google Scholar]
- 30.Cengiz MF, Catal M, Erler F, Bilgin AK. Rapid and sensitive determination of the prochloraz residues in the cultivated mushroom, Agaricus bisporus (Lange) Imbach. Anal. Methods. 2014;6:1970–1976. doi: 10.1039/c3ay42293c. [DOI] [Google Scholar]
- 31.Cao XL, Liu SH, Yang XQ, Liu Z, Liu LZ. A Modified QuEChERS Sample Preparation Method for Simultaneous Determination of 62 Pesticide Residues in Edible Fungi Using Gas Chromatography-Triple Quadrupole Mass Spectrometry. Food Anal. Methods. 2016;9:263–274. doi: 10.1007/s12161-015-0200-0. [DOI] [Google Scholar]
- 32.Steen R, Freriks IL, Cofino WP, Brinkman UAT. Large-volume injection in gas chromatographyn ion trap tandem mass spectrometry for the determination of pesticides in the marine environment at the low ng/l level. Anal. Chim. Acta. 1997;353:153–163. doi: 10.1016/s0003-2670(97)87773-2. [DOI] [Google Scholar]
- 33.Hu M, et al. Determination of ametoctradin residue in fruits and vegetables by modified quick, easy, cheap, effective, rugged, and safe method using ultra-performance liquid chromatography/tandem mass spectrometry. Food Chem. 2015;175:395–400. doi: 10.1016/j.foodchem.2014.11.158. [DOI] [PubMed] [Google Scholar]
- 34.Chen X, et al. Simultaneous determination of trifloxystrobin and trifloxystrobin acid residue in rice and soil by a modified quick, easy, cheap, effective, rugged, and safe method using ultra high performance liquid chromatography with tandem mass spectrometry. J. Sep. Sci. 2014;37:1640–1647. doi: 10.1002/jssc.201400157. [DOI] [PubMed] [Google Scholar]
- 35.Rejczak T, Tuzimski T. Method Development for Sulfonylurea Herbicides Analysis in Rapeseed Oil Samples by HPLC-DAD: Comparison of Zirconium-Based Sorbents and EMR-Lipid for Clean-up of QuEChERS Extract. Food Anal. Methods. 2017;10:3666–3679. doi: 10.1007/s12161-017-0939-6. [DOI] [Google Scholar]
- 36.Poole CF. Matrix-induced response enhancement in pesticide residue analysis by gas chromatography. J. Chromatogr. A. 2007;1158:241–250. doi: 10.1016/j.chroma.2007.01.018. [DOI] [PubMed] [Google Scholar]
- 37.Erney DR, Poole CF. A study of single compound additives to minimize the matrix induced chromatographic response enhancement observed in the gas chromatography of pesticide residues. J.High Resolut. Chromatogr. 1993;16:501–503. doi: 10.1002/jhrc.1240160812. [DOI] [Google Scholar]
- 38.Li M, et al. Determination of cyflumetofen residue in water, soil, and fruits by modified quick, easy, cheap, effective, rugged, and safe method coupled to gas chromatography/tandem mass spectrometry. J. Sep. Sci. 2012;35:2743–2749. doi: 10.1002/jssc.201200349. [DOI] [PubMed] [Google Scholar]
- 39.Zhang W, et al. Simultaneous determination of three strobilurin fungicide residues in fruits, vegetables and soil by a modified quick, easy, cheap, effective, rugged (QuEChERS) method coupled with gas chromatography-tandem mass spectrometry. Anal. Methods. 2013;5:7102–7109. doi: 10.1039/c3ay41417e. [DOI] [Google Scholar]