Determination of 14 Organophosphorus Pesticide Residues in Mutton by Gel Permeation Chromatography-Gas Chromatography-Mass Spectrometry(GPC-GC-MS)

[Objectives]This study was conducted to purify mutton samples by gel permeation chromatography(GPC).[Methods]Fourteen organophosphorus pesticide residues in samples were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry(GC-MS)in selective ion scanning mode(SIM).[Results]The organophosphorus pesticide standard solutions showed good linearity in the mass concentration range of 0.1-10.0μg/ml with correlation coefficients(r)not lower than 0.999,and the detection limits(S=3 N)ranged from 0.01 to 0.05 mg/kg.The average recovery values were in the range of 80.2%-99.7%,with relative standard deviations(RSDs,n=3)in the range of 1.8%-6.3%,at the addition levels of 0.5,1.0 and 2.0 mg/kg.[Conclusions]The method is simple,sensitive and accurate,and can be used for the determination of organophosphorus pesticide residues in mutton.

Research Progress of QuEChERS Pretreatment Technique in the Detection of Multiple Pesticide Residues

The QuEChERS extraction technique is a pretreatment technique that has been rapidly applied in recent years and is widely used in the field of pesticide residues with many advantages. This technique is based on solid phase extraction (SPE), which uses the interaction between adsorbent and impurities in the matrix to achieve the purpose of purification. The method has easier operation and better purification effect than SPE. In this paper, the research progress of the QuEChERS technique in pesticide residue detection in different fields in recent years and its future development were reviewed, hoping to provide reference for further development and utilization of the QuEChERS technique in pesticide residue detection in the future.

Determination of 2 Amides Pesticide Residues in Agricultural Products by Terahertz Time-domain Spectroscopy

[Objective] The aim was to explore the application of terahertz （THz） technique in pesticide recognition and residue determination. [Method] THz far-infrared spectral characteristics of 2 herbicides （butachlor and metolachlor） were measured by THz time-domain spectroscopy （THz-TDS） under conditions of room temperature and nitrogen,meanwhile their refractive index and absorption coefficient between 0.2 and 2.2 THz were calculated by using models based on Fresenl equations. [Result] The 2 pesticides both had a series of different characteristic absorption peaks between 0.2 and 2.2 THz,respectively. Their molecular structures were similar,but there were great difference in absorption and refractive index spectrum between them. [Conclusion] THz-TDS technique is feasible to detect pesticide residues,especially there is a greater advantage in identifying the structure of similar substances.

Simultaneous Determination of Four Pesticide Residues in Fruit Juice by HPLC

[Objective] This study was conducted to develop a system for simultaneous determination of imidacloprid, diflubenzuron, thiabendazole and carbendazim in fruit juice by HPLC. [Method] Using acetonitrile as the extraction solvent, the pesticides in fruit juice were purified through a NH2 solid phase extraction （SPE） cartridge, then detected by HPLC. [Result] There was a good linear relationship between the peak area and the concentrations of imidacloprid, diflubenzuron, thiabendazole and carbendazim in a range of 0.05-5.0 μg/ml, and the linear correlation coefficient varied in a range of 0.999 0-0.999 8; the limit of detection for imidacloprid, diflubenzuron, thiabendazole and carbendazim was 0.003, 0.005, 0.003 and 0.007 mg/kg, respectively. The recovery rate of imidacloprid, diflubenzuron, thiabendazole and carbendazim standards added at three levels （0.1, 0.5 and 1.0 mg/kg） ranged from 82% to 107%, with RSD less than 4.5%. [Conclusion] The sensitivity, accuracy and precision of this method were able to meet the requirements for pesticide residue analysis.

Determination of 10 Pyrethroids Pesticide Residues in Rice by GC-MS-MS

[Objective] A method was developed for the determination of 10 pyrethroids pesticide residues in rice by GC-MS-MS. [Method] Pyrethroids were extracted with acetonitrile, followed by a salting-out step with anhydrous magnesium sulfate and sodium chloride, cleaned up by florisil solid phase extraction （SPE） cartridge, and determined by multiple reaction monitoring mode. [Result] The method showed good linearity over the range of 0.010-0.500 mg/L for 10 pyrethroid pesticide with correlation coefficients over 0.99. The detection limits were 0.005 -0.010 mg/kg. The method was validated by analyzing samples spiked with 0.05, 0.10, 0.20 mg/kg of 10 pyrethroid pesticides, respectively. The average recoveries in rice ranged from 75.0-115.5%, and the relative standard deviations （RSD） were between 3.9%-6.9%. [Conclusion] The method is easy, accurate and reliable, which can meet the requirement for the simultaneous determination and confirmation of pyrethroid pesticide residues in rice.

Investigation and Analysis of Pesticide Residues in Citrus from Parts of Hubei Province

The analysis of pesticide residues in Citrus from Yichang, Danjiangkou, Zigui and Xingshan in Hubei Province was accomplished by UPLC-MS and GC-MS. The results showed that the detection rate of pesticide residues in Citrus reticulate was 91.9%. The detection rate of banned pesticides was 1.6%. The detection rate of restricted pesticides was 9.5%. The detection rate of allowed pesticides was 68.3%. The detection rate of unregistered pesticides was 15.9%. The pesticide used in citrus was relatively common. Because of the banned and restricted pesticides were both in the control degree, on the whole, the quality and security of Citrus reticulata was safe.

Statistical Analysis of Regularity of Pesticide Residues in Vegetables Produced in Inner Mongoli

[Objective]The paper was to study regularity of pesticide residues in vegetables produced in Inner Mongolia.[Method]Mathematical statistic analysis was carried out on 6 800 samples of veggies,fruits,leguminous vegetables,nuts and seeds produced in Inner Mongolia.[Result]The dominated vegetables in Inner Mongolia were green leafy vegetables,solanaceous vegetables and melon vegetables,and their yields accounted for 70%of the total vegetables production.Since 2003,with the rapid increase of detected vegetable numbers,the status of vegetable quality safety had entered into a new stage of sustainable steady after a rapid decline or periodic fluctuation,and the differences in safety levels were obvious,of which the range of exceeding standard rate of pesticide residues in solanaceous vegetables,melon vegetables and leguminous vegetables(about 55%of the total vegetables)was under 2%,with average values of 1.1%,1.6%and 3.1%,respectively.They belonged to stable type.The exceeding standard rate of pesticide residues in green leafy vegetables and Chinese cabbage group(about 30%of total vegetables)presented a decreasing trend year by year,wondering in the range of 7%-10%.They belonged to main risk type.The time period of exceeding standard of pesticide residues in root vegetables and cole vegetables was under predictable,and its exceeding standard rate in some years was over 5%(amplitude variation is over 15percentage points).They belonged to random risk type.The kinds of pesticides,which exceeding standard rate in vegetables were relatively intensive,presented variance in different vegetable species.70%of the pesticides belonged to intermittent over-limits and the probability was below 5%.About 20%tradition pesticides often exceeded standard and their probabilities were over 30%.The exceeding standard of organophosphorus and carbamates pesticides in vegetables presented a decreasing tend,while the risk of some new pesticides containing nitrogen element and high effective pyrethroids showed an increasing tendency.[Conclusion]The paper provided decision making services for agricultural management departments.

Study on Pesticide Residues of Phorate and Emamectin Benzoate in Cauliflower with Ball Well Protected

In order to study the difference between cauliflower varieties with ball well protected and unprotected in terms of pesticide residue and its causes, Jinpin 70, a new male sterile cauliflower variety with ball well protected, and Xuebao with ball unprotected were sprayed with high-toxic pesticide phorate and efficient bio-pesticide emamectin benzoate at a regular dose to investigate the impact of different cauliflower varieties on the pesticide residue. The results showed that from the 3rd to the 5th day after spraying, phorate and emamectin benzoate residues in Jinpin 70 with ball well protected reduced by 76.47%-87.65% and 67.86%-80.82% re- spectively compared with Xubao, and decreased by 9.23%-81.82% and 57.14%- 79.84% respectively compared with Jinpin 70 with ball unprotected. The results above demonstrates that inner leaves of cauliflower with ball well protected can prevent the ball from being polluted by phorate and emamectin benzoate, thereby improving its edible safety.

Study on Prediction of Pesticide Residues Based on Fuzzy System

This study was aimed to do the prediction of pesticide residues based on fuzzy system. Taking chlorpyrifos as an example, the Mathematic Fuzzy System was established by using the MRL values （maximum residue limits of all kinds of pesticides in food） of the Matlab Fuzzy Toolbox to analyze and predict the degra- dation degree of pesticide residues of the same crop at different time periods of bagging treatment, with the aim to provide some theoretical guidances for solving practical problems in real life.

Analysis of pesticide residues in commercially available chenpi using a modified QuEChERS method and GC-MS/MS determination

To ensure the safety of the commercially available chenpi,a convenient and fast analytical method was developed for the determination of 133 pesticide residues in chenpi using gas chromatography-tandem mass spectrometry(GC-MS/MS).In this study,different extraction solvents,redissolution solvents and adsorbents were tested according to the recovery and purification effect to obtain a modified QuEChERS method.The samples were extracted with acetonitrile.During the clean-up step,octadecyl-modified silica(C18)and graphitized carbon black(GCB)were selected,and aminopropyl(NH2)was used instead of primary secondary amine(PSA)because of its weaker ion exchange capacity which had little effect on the recovery of ditalimfos.Samples were quantified by matrix-matched calibration with internal standards.All pesticides showed good linearity in the respective range,both with values of r2>0.99.The average recoveries of the pesticides spiked samples ranged from 70.0% to 112.2% with the RSDs of 0.2%–14.4%.The modified QuEChERS method was validated and applied to twenty real samples.Five pesticides were found in eight batches,but no pesticide exceeded the maximum residue limits(MRL,MRL reference to European commission).

Risk assessment and ranking of pesticide residues in Chinese pears

The presence of pesticide residues in pears is a serious health concern. This study presents the results from a 2-year investigation （2013-2014） that used gas chromatography, GS/MS and UPLC/MS-MS to measure the levels of 104 pesti- cides in 310 pear samples. In 93.2% of the samples, 43 pesticides were detected, of which the maximum residue levels （MRLs） were exceeded in 2.6% of the samples. Multiple residues （two to eight compounds） were present in 69.7% of the samples; one sample contained nine pesticides and one sample contained 10. Only 6.8% of the samples did not contain residues. To assess the health risks, the pesticide residue data have been combined with daily pear consumption data for children and adult populations. A deterministic model was used to assess the chronic and acute exposures based on the Joint Meeting on Pesticide Residues （JMPR） method. A potential acute risk was demonstrated for children in the case of bifenthrin, which was found to be present at 105.36% of the acute reference dose （ARfD） value. The long- term exposure of the Chinese consumer to pesticide residues through the consumption of raw pears was far below the acceptable daily intake （ADI） criterion. Additionally, the matrix ranking scheme was used to classify risk subgroups of pesticides and pear samples. In general, 95.5% of samples were deemed to be safe and nine pesticides were classified as being of a relatively high risk. The findings indicated that the occurrence of pesticide residues in pears should not be considered a serious public health problem. Nevertheless, a more detailed study is required for vulnerable consumer groups, especially children. Continuous monitoring of pesticides in pears and tighter regulation of pesticide residue standards are recommended.

Simultaneous Determination of 8 Pesticide Residues in Green Tea Based on Gas Chromatography-mass Spectrometry

To improve pesticide residues detection efficiency in tea, simultaneous de- termination of eight pesticide residues in green tea was developed based on gas chromatography-mass spectrometry （GC-MS）. The results showed that, - detected by the GC-MS under following conditions： acetonitrile as extraction and elution solvent, activated carbon and PSA tandem column as the stationary phase, elution volume of 12 ml the relationship between peak area and concentration of each residue （ametryn in the range of 0-100 pg/L, napropamide in the range of 0-10 000 gg/L, other pesticides in the range of 0-1 000 tJg/L） were linearly related, and their corre- lation coefficients were all greater than 0.999. The recovery rate the pesticides added to tea sample at legal concentration limits ranged from 73.6% to 116.8%, and the relative standard deviation from 1.47% to 15.58%. The new method we de- veloped is sensitive, specific and anti-interference, and thus provides test basis for the development of pesticide matrix reference materials in tea.

Management of pesticide residues in China

This paper reviewed management of pesticide residues in China including laws and regulations, the supervision system, the standard system, and the quality and safety of agricultural products. The process of establishment and internationalization of standards for pesticide residues were also discussed. Results indicate that the progress of the management of pesticide residues has been steadily made in China. However, the following aspects which refer to updates to regulations, supervising efficiency, standard system, risk assessment, international cooperation and communication, should be further improved. China should draw lessons from international experience, and then establish its own management system, which focuses on pesticides controls by strictly following relevant laws and technical standards to ensure the quality and safety of agricultural products.

Effects of Two Composted Plant Pesticide Residues,Incorporated with Trichoderma viride,on Root-Knot Nematode in Balloonflower

Plant pesticide residues, such as chinaberry （Melia toosendan） residue and sand cypress （Sabina vulgaris） residue, are pesticidal plant materials discarded after the bioactive ingredient has been extracted with organic solvents. The only option for botanical pesticide residue utilization has been as landfill. Chinaberry residue （CBR） and sand cypress residue （SCR） were collected and composted in Yangling, Shaanxi Province, China. We studied the effects of chinaberry residue compost （CBRC）, CBRC incorporated with Trichoderma viride （CBRCT）, sand cypress residue compost （SCRC）, and SCRC incorporated with T. viride （SCRCv） on the root-knot nematode, Meloidogyne incognita, infesting the balloonflower （Platycodon grandiflorum）. Bioassay results indicated that stock solutions of the CBRCT and SCRCT extracts significantly inhibited egg hatching and caused high larval mortality, followed in degree by the CBRC and SCRC extracts. The CBR and SCR extracts caused very low inhibition of eggs and larvae. Supplementing potting mixtures with these four composts reduced the severity of root galling and increased the proportion of marketable roots. The severity of root galling decreased and the average weight of the marketable roots increased with an increase in all the composts when supplemented at rates from 5 to 30%. CBR- and SCR-supplemented pot soils also inhibited the nematodes, but CBR and SCR applied to the soil had a phytotoxic effect and inhibited balloonflower growth. Supplementing field soil with the composts reduced the severity of root galling and the populations of southern root-knot nematodes in the soil. CBRCT and SCRCT clearly enhanced the average weight of the marketable roots by 30.45 and 26.64%, respectively. Continuous supplementation with CBRCT or SCRCT in the same field significantly enhanced the control of the root-knot nematode, and the populations of nematodes continued to decrease with second inoculations. The populations of total Trichoderma spp. were distinctly enhanced and were maintained at high levels for a long time in the supplemented soils.

Simultaneous determination of 74 pesticide residues in Panax notoginseng by QuEChERS coupled with gas chromatography tandem mass spectrometry

This study established a method for the simultaneous determination of 74 pesticide residues in Panax notoginseng by QuEChERS pretreatment method coupled with GC-MS/MS,and carried out pesticide residue analysis on 20 batches of market samples in China.The samples were extracted with acetonitrile,cleaned up with primary secondary amine(PSA)and octadecylsilane(C18)and determined by GC-MS/MS in multiple reaction monitoring(MRM)mode.Matrix-matched calibration was recommended to combat the matrix effect.A good linearity was observed in the range of 10−500 ng/mL with correlation coefficients≥0.9950.The mean recoveries for most of the pesticides were in the range of 70%−120%with RSD<20%.The limits of detection ranged 0.28–2.00μg/kg,while the limits of quantification were 0.94–6.65μg/kg.Following the application of“top-down”approach,the expanded measurement uncertainty for all the analytes was<30%.The proposed method was successfully applied to determine pesticide residues in 20 market samples in China,where 9 pesticides were detected and quintozene exceeded the criteria domestically and abroad.

Rapid screening of 420 pesticide residues in fruits and vegetables using ultra high performance liquid chromatography combined with quadrupole-time of flight mass spectrometry

A new method for screening and identification 420 pesticide residues in fruits and vegetables by ultra-performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry(UPLC-Q-TOF/MS)were developed.The samples were extracted with acetonitrile/acetic acid(99:1,V/V),and clean-up by SinChERS-Nano(single-step,cheap,effective,rugged,safe,nano)column,determined by UPLC-Q-TOF/MS.The accurate mass database and MS/MS database which contains 420 pesticides were established,the automatic retrieval of detection results was carried on according to the accurate mass,retention time,isotope ratio,ion fragment information,and so on.Method verification was performed on leeks samples.The results showed that 420 pesticides had good linearity in the range of 0.1-100μg/L,and the correlation coeffificients(R2)was greater than 0.990.The limits of detections(LODs)and limits of quantifications(LOQs)of 420 pesticides were in range of 0.05-2.0 and 0.1-5.0μg/L,respectively.The average spike recoveries at 3 levels were 70.1%to 119.7%,and the relative standard deviations(RSD)were lower than 20%(n=6).With this method,a survey of pesticide residues was conducted for 110 samples of 10 different fruits and vegetables,which provided scientific data for ensuring pesticide residue safety of the fruits and vegetables consumed daily by the public.This method was simple,sensitive and accurate,and could be used for rapid screening of 420 pesticide residues in fruits and vegetables.

Simultaneous determination of 15 pesticide residues in Chinese cabbage and cucumber by liquid chromatography-tandem mass spectrometry utilizing online turbulent flow chromatography

In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purification.After modified quick,easy,cheap,effective,rugged,and safe(QuEChERS)extraction,extracts were directly injected to the TLX(TurboFlow Liquid Xcalibur)system and brought to TurboFlow™columns for on-line purification and then transferred to analytical column for further separation and analysis.TurboFlow™columns types,transfer flow rate,and transfer time were optimized.Limits of detection and limits of quantification of the method obtained for 15 pesticide residues were ranged between 0.2–1.0μg/kg and 0.5–2.0μg/kg in Chinese cabbage and cucumber samples.Recoveries of pesticide residues were in range of 75.3%–103.7%.Matrix effects for 15 pesticides were in range of 5.6%–106.6%.The developed method has been successfully used for the determination of 15 pesticide residues in real samples.

Determination of Eight Organophosphorus Pesticide Residues in Pepper by QuEChERS-Gas Chromatography

[ Objectives] This study was conducted to establish a QuEChERS-gas chromatography method for determination of eight kinds of organophosphorus pesticide residues in pepper. [Methods] The samples were extracted by acetonitrile, and anhydrous magnesium sulfate was used for salting out. The extracts were then purified by dispersive solid phase extraction combining with GCB, C18 and PSA. Samples were analyzed by FPD detector. External standard was used as quantitive method. [ Results] The detection limits were in the range of 0. 001 -0. 008 mg/kg, the average recoveries ranged from 83.5% to 101.2% , and the relative standard deviation （RSD） of the eight organophosphorus pesticide residues were below 5%. [ Conclusions] The method is simple, quick, easy and effective for the determination of pepper.

Pesticide Residues and Government Regulation in China─Evidence from Pesticide Residues in Fruits and Vegetables

China is a big producer and exporter of fruits and vegetables,and pesticide residues are an important factor affecting the quality and safety of fruits and vegetables and their export trade.In this paper,we analyzed the pesticide residue data on fruits and vegetables in 32 major Chinese cities between 2012—2019,the export data of Chinese fruits and vegetables and the role of pesticides in foodborne diseases.The results showed that pesticide residues in fruits and vegetables(PRFV)partial excess of maximum residue standard(MRL)and residues of banned pesticide were still widespread in China.By comparing the standards of pesticide residues in the European Union and China and addressing the agricultural situation in China,this paper analyzed the main causes of PRFV in China and put forward some policy suggestions for strengthening government regulation of pesticide application in agricultural products.

Variability of Pesticide Residues in Vegetables from the Marketplaces in Jinan City

In order to provide technological support for risk estimation of pesticide residues taken from vegetables, the residues of pesticide in vegetables in Jinan City, China, were investigated. Moreover, the variability of pesticide residues in vegetables was explored, and the variability factor was calculated. The level of pesticide residue was studied by statistical method. The variability factor was calculated using the Harrell-Davis method in accordance with principles recommended by the JMPR. In addition, the procedure of evaluation was validated according to the principles laid down by the JMPR （Joint Meeting on Pesticide Residues）. The detection rate of pesticide residues in all marketplace samples was less than 20% in Jinan City. The unqualified rate of vegetables was low （0.6%）. The chlorothalonil was found as the pesticide with the highest rate of detection. The vegetables with the highest rate of pesticide residues detected were leafy vegetables. The relationship between variability factor and mean value of concentrations of contaminations was expressed by the formula, v=4.9×Cmean. The pesticide residues in vegetables from Jinan City is low. The evaluated variability factor is larger than that the value recommended by the JMPR, however, less than the default value used for acute intake assessment of pesticide residues in UK in most cases.