Dissipation and residue fate of kresoxim-methyl in tobacco leaves and soil under field conditions

The fate of kresoxim-methyl was studied in a tobacco field ecosystem, and a simple and reliable method was developed for the determination of kresoxim-methyl in soil, green and cured tobacco leaves. Kresoxim-methyl residues were extracted from samples with petroleum ether, and determined by gas chromatography (GC) coupled with an electron capture detector (ECD). Kresoxim-methyl (30% suspension concentration) was applied at 150 g a.i. ha^–1 (the recommended high dosage) and 225 g a.i. ha^–1 (1.5 times the recommended high dosage) in the experimental fields in Huishui and Changsha in China. The limits of detection (LODs) and limits of quantification (LOQs) of kresoxim-methyl in green tobacco leaves, cured tobacco leaves and soil were 0.012 and 0.04 mg kg^–1, 0.12 and 0.4 mg kg^–1, and 0.0015 and 0.005 mg kg^–1, respectively. The average recoveries were 84.5% to 95.7%, 79.8% to 94.3% and 83.3% to 93.8% with relative standard deviations (RSDs) less than 10% in green tobacco leaves at four spiked levels (0.04, 0.2, 2 and 8 mg kg^–1), cured tobacco leaves at three spiked levels (0.4, 1 and 10 mg kg^–1) and soil at three spiked levels (0.005, 0.05 and 0.5 mg kg^–1), respectively. The results showed that the half-lives of kresoxim-methyl in green tobacco leaves and soil were 1.2–5.3 days and 6.7–10.4 days, respectively. At harvest, kresoxim-methyl residues in cured tobacco leaves samples collected 21 days after the last application at the recommended dosage were below 1.0 mg kg^–1. These results could help establish appropriate application frequency and harvest intervals in the use of kresoxim-methyl on tobacco plants.     

Residue and dissipation of zinc thiazole in tobacco field ecosystem

A high-performance liquid chromatography with ultraviolet (HPLC-UV) detection method after derivatisation was developed for the first time for the novel fungicide zinc thiazole residue in tobacco samples. Field trials in two different locations were conducted to investigate the dissipation and residue of zinc thiazole in tobacco leaves and soil. The average recoveries of zinc thiazole were in the range of 82.5%–93.9% with relative standard deviations (RSDs) of 1.2%–9.1%. The zinc thiazole showed a rapid dissipation rate in fresh tobacco leaves with the half-lives of 1.1–1.6 days. The terminal residues of zinc thiazole in cured tobacco leaves and soil were 2.8–28.0 mg kg^?1and <0.05 mg kg^?1, respectively. The results could be used to establish the maximum residue limits (MRLs) and provide guidance for the scientific use of zinc thiazole in agriculture.     

Persistence and dissipation of fluopicolide and propamocarb on cabbage and soil under semi-arid climatic conditions

Persistence and dissipation of fluopicolide and propamocarb were studied on cabbage and soil as per good agricultural practices over a period of 2 years. A modified QuEChERS analytical method in conjunction with gas chromatography (GC) and GC–mass spectrometry was used for analysis of fluopicolide and its metabolite, 2,6-dichlorobenzamide, and propamocarb in cabbage and soil. The results of the method validation were satisfactory with recoveries within 74.5–100.81% and relative standard deviations 4.8–13.9% (n = 6). The limit of detection (LOD) and limit of quantification (LOQ) of both fluopicolide and 2,6-dichlorobenzamide were 0.003 µg mL^?1 and 0.01 mg kg^?1, respectively. The LOD and LOQ of propamocarb were 0.03 µg mL^?1 and 0.1 mg kg^?1, respectively. During 2013, the initial residue deposits of fluopicolide on cabbage were 0.60 and 1.48 mg kg^?1 from treatments at the standard and double doses of 100 and 200 g a.i. ha^?1 which dissipated with the half-life of 3.4 and 3.7 days. During 2014, the residues were 0.49 and 1.13 mg kg^?1 which dissipated with the half-life of 4.2 and 5.1 days. Propamocarb residues on cabbage were 5.36 and 12.58 mg kg^?1 in the first study (2013) and 4.85 and 10.26 mg kg^?1 in the second study (2014) from treatments at the standard and double doses of 1000 and 2000 g a.i. ha^?1, respectively. The residues dissipated with the half-life of 4–5.5 days. The preharvest interval, the time required for fluopicolide + propamocarb residues to dissipate below the maximum residue limits (notified by EU) at the standard dose, was 11.8 and 14 days during 2013 and 2014. Residue of 2,6-dichlorobenzamide was always <LOQ in cabbage. Residues of fluopicolide, 2,6-dichlorobenzamide and propamocarb were <LOQ in field soil at harvest.     

Simultaneous Analysis of Hexaconazole, Myclobutanil, and Tebuconazole Residues in Apples and Soil by SPE Clean-Up and GC with Nitrogen–Phosphorus Detection

A facile and sensitive method utilizing capillary gas chromatography with nitrogen phosphorus detection (GC–NPD) has been developed and validated for simultaneous analysis of hexaconazole, myclobutanil, and tebuconazole, three broad-spectrum systemic fungicides, in apples and soil. Two samples were fortified with the three pesticides and subjected to ultrasonic extraction, followed by solid-phase extraction (SPE) to remove coextractives, before analysis by GC–NPD. SPE procedures were performed on PSA cartridges (500 mg, 3 mL), the analytes being eluted with n-hexane–acetone (9:1 v/v, 2 mL). Recovery of three pesticides from the fortified apple and soil samples ranged from 94.5 to 107.3% with relative standard deviations less than 9.7% at the three spike levels (0.01, 0.1, and 0.5 mg kg^?1). Limits of quantification of the method for apple and soil were 0.01 mg kg^?1, sufficiently below the maximum residue limits. Direct confirmation of the analytes in samples was achieved by gas chromatography–mass spectrometry (GC–MS).     

Analysis of residue dynamics of clofentezine in tangerine and field soil by QuEChERS and HPLC-UV methods

A field experiment was conducted to evaluate clofentezine residue levels and dissipation trend in tangerine and soil for the safe application of clofentezine. A modified QuEChERS-HPLC-UVD method was developed to analyse clofentezine in tangerine and soil. Tangerine samples were homogenised and extracted by acetonitrile and then cleaned up with dispersive solid phase extraction (dSPE) by primary and secondary amine (PSA) and C₁₈. Clofentezine residue was determined by high-performance liquid chromatography (HPLC) with a UV detector (UVD) at the wavelength of 268 nm. The presented method achieved the good linear relationship within the range from 0.05 to 5.0 mg kg^?1 for clofentezine (R² > 0.998). At the fortification levels of 0.05, 0.50 and 1.00 mg kg^?1 in tangerine pulp, tangerine peel and soil, recoveries ranged from 75.9% to 117.7% with relative standard deviations (RSD) less than 8.2%. In the supervised field trials, the half-lives of clofentezine in tangerine and soil were approximately 11.3 and 8.6 days, respectively. At pre-harvest interval of 21 days, the residue of clofentezine in tangerine was below the maximum residue limits (MRL) (0.5 mg kg^?1). Clofentezine (Water Dispersible Granule, 80%) was recommended to be sprayed twice and the recommended dosage ranged from 250 to 375 mg kg^?1.     

Residues and risk assessment of bifenthrin and chlorfenapyr in eggplant and soil under open ecosystem conditions

Dissipation and residue levels of bifenthrin and chlorfenapyr in eggplant and soil under field conditions were investigated using gas chromatography coupled with an electron capture detector (GC-ECD). The mean recoveries of bifenthrin and chlorfenapyr were 85.2–104.9%, with relative standard deviations (RSDs) of 0.5–9.1%. The limit of quantification (LOQ) was 0.01 mg kg^?1. Bifenthrin exhibited half-lives of 3.3 to 4.1 days in eggplant and 17.8 to 25.7 days in soil; the half-lives of chlorfenapyr were 3.5 to 3.8 days in eggplant and 21.7 to 27.7 days in soil. During harvest, the terminal residues of bifenthrin and chlorfenapyr were below 0.031 and 0.083 mg kg^?1, respectively. Risk assessment for different groups of people in China was evaluated. The risk quotients (RQs) of bifenthrin and chlorfenapyr were ranged from 0.0068 to 0.0148 and from 0.0033 to 0.0072, respectively. These results may provide guidance on reasonable use of pesticides and serve as a basis for establishing maximum residue limits (MRLs) in China.     

A multi-residue method for pesticide residue analysis in rice grains using matrix solid-phase dispersion extraction and high-performance liquid chromatography–diode array detection

Pesticides are widely used in rice cultivation, often resulting in detection of their residues in rice grains. So far, no analytical method has been available for the simultaneous determination of most rice pesticides in rice grains. This paper reports the development and validation of such a method for the determination of eight rice pesticides (penoxsulam tricyclazole, propanil, azoxystrobin, molinate, profoxydim, cyhalofop-butyl, deltamethrin) and 3,4-dichloroaniline, the main metabolite of propanil. Pesticide extraction and clean-up was performed by an optimized matrix solid-phase dispersion (MSPD) protocol on neutral alumina (5 g) using acetonitrile as the elution solvent. Samples were analyzed in a high-performance liquid chromatography–diode array detection (HPLC-DAD) system. Pesticide separation was achieved with a mobile phase of acetonitrile/water in a linear elution gradient from 30:70% (v/v) to 100:0% (v/v) in 14 min at a flow rate of 0.8 mL min^?1. Method validation was performed by means of linearity, intra-day accuracy, inter-day precision and sensitivity. Linear regression coefficients (R ²) were always above 0.9948. Limits of detection (LOD) and quantification (LOQ) varied from 0.002 to 0.200 mg kg^?1 and 0.006 to 0.600 mg kg^?1, respectively. Recoveries were investigated at three fortification levels and were found to be acceptable (74–127%) with relative standard deviations (RSD) below 12%. Application of the method for the analysis of five commercial rice grain samples showed that the pesticide levels were below the LOD. Overall, the method developed is suitable for the determination of residues of most rice pesticides in rice grains at levels below the established MRLs.     

Dissipation dynamics and final residues of flutriafol in tobacco and soil using ultrasound-assisted extraction before liquid chromatography/tandem mass spectrometry

The dissipation dynamics and final residues of flutriafol on tobacco plant and soil were studied under field conditions. The residues of flutriafol in soil, green tobacco leaves and cured tobacco leaves were extracted by ultrasound-assisted extraction, cleaned up by dispersive solid-phase extraction and detected by liquid chromatography with tandem mass spectrometry. The limits of detection of flutriafol in soil, green tobacco leaves and cured tobacco leaves were 0.006, 0.033 and 0.033 mg·kg^?1, respectively. The limits of quantification of flutriafol in soil, green tobacco leaves and cured tobacco leaves were 0.02, 0.1 and 0.1 mg·kg^?1, respectively. Recoveries were 72.9–102% with relative standard deviations of less than 12% in soil and tobacco matrix. For field experiments, the half-lives of flutriafol in soil and green tobacco leaves were 9.2–11.5 and 9.5–11.1 days, respectively. At harvest, the final residue levels of flutriafol in cured tobacco leaves collected 21 days after one application at the recommended dosage were below 2.0 mg/kg. The maximum residue limit maximum residue limit (MRL) for flutriafol in tobacco has not yet been established in any countries. The data could help the Chinese Government to establish the MRL of flutriafol in tobacco and provide guidance on the proper use of flutriafol.     

Analysis of bioaccessible concentration of trace elements in plant based edible materials by INAA and ICPMS methods

The total metal concentration and bioaccessible concentration of Cr, Mn, Fe, Cu, Zn, Se in Momordica charantia, Asparagus racemosus, Terminalia arjuna and Syzyzium cumini were measured by instrumental neutron activation analysis and by inductively coupled plasma mass spectrometry analysis (ICP-MS). The bioaccessible concentrations were determined in the gastrointestinal digest obtained after treating dried powdered samples sequentially in gastric and intestinal fluid of porcine origin at physiological conditions. The bioaccessible concentration of Fe was in the range of 58–67 mg kg^?1, Mn was 10.2–14.6 mg kg^?1, Cu was 3.7–4.8 mg kg^?1 and Zn was 10.6–18.4 mg kg^?1, were within the safety limits set for vegetable food stuff set by Joint FAO/WHO. The bioaccessibility of Zn, an essential element, was high (40–50 %) in M. charantia and in S. cumini. In addition, the total metal contents and bioaccessible concentration of Ni, Se, Cd and Pb in these samples were measured by ICP-MS. The total Cd content in S. cumini (2.6 ± 0.2 mg kg^?1) and its bioaccessible concentration (0.6 mg kg^?1) were strikingly high as compared to the other samples. Though total Hg contents were determined by ICP-MS, but their bioaccessible concentrations were below the detection limit (0.036 mg kg^?1).     

Transfer of Metals from Soil to Crops in an Area near a Coal Gangue Pile in the Guqiao Coal Mine,China

A field survey was conducted to investigate the metal contamination in coal gangue, soils, and crops (rice and soybeans), and to evaluate the possible health risks to the local population through food chain transfer near a coal gangue pile in the Guqiao Coal Mine, China. Contamination levels of zinc, lead, cadmium, and copper in coal gangue, soils, and crops were measured, and bio-accumulation factors from soil to crops were determined; the health risks were calculated accordingly. Results showed that both coal gangue and soil contained high levels of cadmium (0.15 mg kg^?1and 0.20 mg kg^?1) exceeding the background value of the soil. The lead soil concentration was low (9.99 mg kg^?1), but lead in rice (0.38 mg kg^?1) exceeded the maximal permissible limit of 0.2 mg kg^?1. For some tissues of crops studied, there was a significant correlation between the bio-accumulation factor values and the corresponding soil metal concentrations that were best described by a power equation. Oral intake of zinc, cadmium, and copper through crops posed no health risk to local residents, although hazard indices for rice (0.87–2.88) and soybeans (0.06–0.09) suggested that ingestion of rice grains was unsafe for human health. Therefore, rice was inappropriate to be planted in the soil surrounding this coal mine.     

Dissipation kinetics and risk assessment of fluopyram and tebuconazole in mango (Mangifera indica)

The combination formulation of fluopyram and tebuconazole is used for control of fungal diseases and post-harvest disease management of mango. Dissipation study of the fungicides on mango was carried out after giving applications of fluopyram +tebuconazole at the standard and double doses of 150 + 150 and 300 + 300 g active ingredient hectare^?1 (g a.i. ha^?1), respectively. Fluopyram residues on mango were 0.8 and 0.9 mg kg^?1 and tebuconazole residues, 0.308 and 0.4 mg kg^?1 after three and four applications at the standard dose. At double dose treatment the residue levels for fluopyram were 1.266 and 1.453 mg kg^?1 and tebuconazole, 0.681 and 0.853 mg kg^?1, respectively. Residue dissipation in mango fruits followed first order rate kinetics and the half-life (DT₅₀) were 4.3–5.4 days for fluopyram and 3–3.8 days for tebuconazole. Faster dissipation of the fungicides was observed after the fourth treatment which directly correlated to higher rainfall during that period. The combined residues of fluopyram+tebuconazole reduced to below their maximum residue limits (MRLs) within 36–38 days. Dietary risk assessment on human health indicated that fluopyram and tebuconazole application to mango is unlikely to pose risk to human beings. This study gives valuable information on the judicious use of this combination formulation on mango, especially towards harvest.     

Erratum to: Evaluation of Three Multiresidue Methods for the Determination of Pesticides in Marijuana (Cannabis sativa L.) with Liquid Chromatography-Tandem Mass Spectrometry

Marijuana (non-medical cannabis) is a well-recognized psychoactive herbal drug used for recreational purposes. The aim of this work is to describe and compare the performance and suitability of selected methods to analyze pesticide residues in marijuana. The fitness of three typical pesticide multiresidue methods [acetate buffered QuEChERS (method A), a modified citrate buffered QuEChERS (method B) and citrate buffered QuEChERS (method C)] were tested in marijuana through the LC–MS/MS determination of 61 LC amenable pesticides. Considering recoveries at the highest level for the selected pesticides in marijuana, from the 61 target analytes, 37 (method A), 40 (method B) and 46 (method C) compounds gave accurate results (70–120 % range). Method C showed the best performance for the target analytes in terms of recoveries, precision, limits of quantitation and matrix effect. Marijuana showed to be a highly complex matrix. Most analytes suffered high signal suppression (ME <−50 %) for method B while medium (−50 to 20 %) to low (−20 to 0 %) signal suppression was found for methods A and C. Moreover, high coelution of coextractives with the target analytes was observed. A pilot survey with real samples revealed that seized and legally produced marijuana samples contained pesticides. Residues of diazinon (0.03 mg kg⁻¹), tebuconazole (0.19 mg kg⁻¹) and teflubenzuron (0.11 mg kg⁻¹) were simultaneously detected in one marijuana sample. The establishment of MRLs in a legal consumption scenario such as in Uruguay seems to be necessary in the near future.

     

Pesticide residues analysis in honey using ethyl acetate extraction method: validation and pilot survey in real samples

This paper presents a cost-effective and validated multi residue confirmatory method for the determination of 167 chemically different pesticides and a survey study on Cyprus honey samples. This method uses ethyl acetate for the extraction of pesticides from honey and the determination is performed with liquid chromatography (LC) coupled to mass spectrometry (MS) operating in tandem mode (MS/MS) and with GC–ECD (gas chromatography with electron capture detector) analysis. The LC-MS/MS analytical system is especially important in the analysis of polar and non-volatile pesticides. For the validation of the method, blank honey samples were spiked with 146 pesticides (organophosphorous, carbamates, triazoles, amides, neonicodinoids, strobilurines, phenylureas, bendimidazoles and others) for the LC-MS/MS analysis at three levels: 0.01, 0.05 and 0.1 mg kg^?1 and with 21 pesticides for the GC-ECD analysis at two levels: 0.01 and 0.05 mg kg^?1for organochlorines and 0.05 and 0.2 mg kg^?1for the pyrethroids. As blank sample, a sample of honey which did not contain detectable levels of the analytes sought was used. The validation study was in accordance to the DG SANCO guidelines. The scope of validation included recovery, linearity, limits of quantification and precision. Linearity is demonstrated all along the range of concentration that was investigated with correlation coefficients ≥0.98. Recoveries of the majority of compounds were in the 70%–120% range and were characterised by precision lower or equal to 20%. The validated method was used for a survey of 36 samples of honey produced in different areas of Cyprus and this is the first work on Cypriot honey samples investigating a broad range of pesticides. Only coumaphos was detected at concentrations higher than 0.01 mg kg^?1 in the 58.6% of the honey samples analysed for Coumaphos. The results were evaluated in accordance to the provisions of the Commission Regulation (EU) No 37/2010 on pharmacologically active substances and their classification regarding maximum residue limits (MRLs) in foodstuffs of animal origin. The concentrations of coumaphos in all positive samples were at levels much lower than the MRL.     

Determination of 24 pesticides residues in mineral and peat soils by modified QuEChERS method and gas chromatography

A simple extraction and cleanup procedure has been developed for the analysis of 24 organophosphorus (OP), organochlorine (OC) and pyrethroid (PY) pesticides in mineral and peat soils using modified QuEChERS method. The pesticides were extracted from the soil with acidified acetonitrile. The water was removed from the extract by salting out with sodium chloride and addition of magnesium sulfate. For OP pesticides, the extracts were cleaned up with 0.2 g of primary secondary amine packed in glass Pasteur pipette and determined by gas chromatography with flame photometric detector. For OC and PY pesticides, the extracts were cleaned up with 0.2 g of silica gel packed in a glass Pasteur pipette and determined by gas chromatography with electron capture detector. After the cleanup, the extracts had lower colour intensity and reduced matrix interferences. The recovery of the OP and OC pesticides for mineral and peat soils determined at 0.01–1.0 mg kg^?1 fortification levels ranged from 79.0–120.0% and 82.2–117.6%, respectively. The detection limits for OP and OC pesticides were 0.001–0.01 and 0.002–0.005 mg kg^?1, respectively. The recovery of the PY pesticides ranged from 87.5–111.7% at the detection limits of 0.002–0.010 mg kg^?1. The relative standard deviations for all pesticides studied were below 10.8%. The modified method was simple, fast, and had utilized less reagents than the conventional methods. The method was applied to the determination of the pesticide residues in mineral and peat soil samples collected from the vegetable farms.     

MSPD Procedure for Determination of Carbofuran, Pyrimethanil and Tetraconazole Residues in Banana by GC–MS

An extraction method based on matrix solid-phase dispersion was developed to determine carbofuran, pyrimethanil and tetraconazole in banana using gas chromatography–mass spectrometry. The best results were obtained using 2.0 g of banana, 1.0 g of silica as dispersant sorbent and n-hexane:ethyl acetate (1:4, v/v) as eluting solvent. The method was validated using banana samples fortified with pesticides at different concentration levels (0.05–2.0 mg kg^?1). Average recoveries (four replicates) ranged from 68 to 111%, with relative standard deviations between 6.6 and 20.5%. Detection and quantification limits for banana ranged from 0.02 to 0.05 and 0.05 to 0.10 mg kg^?1, respectively.     

Determination of Cypermethrin Residues in Crucian Carp Tissues by MSPD/GC-ECD

A sensitive matrix solid-phase dispersion (MSPD)/gas chromatography-electron capture detector (GC-ECD) method was developed to determine cypermethrin residues in three tissues (muscle, liver, and gill) of crucian carp. Cypermethrin was simultaneously extracted by MSPD and determined by GC-ECD. The main parameters affecting extraction yield and selectivity, such as the type of solid adsorbent material, choice of elution solvents and their volume, were investigated to obtain interference-free extracts and quantitative cypermethrin recovery. Fortified recoveries in muscle, liver, and gill samples ranged from 84.9% to 106.1%, and relative standard deviations were <8% with fortification levels of 0.05–1 mg kg^?1. Detection limits were 1.4–2.1 μg kg^?1, and quantitation limits were 5.8–7.8 μg kg^?1. The proposed method was successfully applied to determination of cypermethrin in fish tissue samples.     

Residue dynamics of chlorpyrifos and cypermethrin in/on pomegranate (Punica granatum L.) fruits and soil

Study on the residue dynamics of chlorpyrifos and cypermethrin in/on pomegranate (Punica granatum L.) and soil was carried out by conducting supervised field trials as per good agricultural practices. A modified QuEChERS was used to extract the insecticides in pomegranate peel and aril and soil. The limit of quantification (LOQ) of chlorpyrifos and cypermethrin were 0.01 and 0.05 mg kg^?1, respectively. Residues of the insecticides remained on the fruit surface and movement to the edible part (aril) was not observed. The residues after treatment on fruit peel were 2.46 and 3.51 mg kg^?1 and 2.84 and 4.54 mg kg^?1 for chlorpyrifos and cypermethrin, respectively, from recommended and double dose treatments. Chlorpyrifos residues degraded faster compared to cypermethrin. The pre-harvest intervals (PHIs) of chlorpyrifos were 22 and 35 days and those of cypermethrin 50 and 73 days, respectively, at recommended and double dose treatments. In the experimental field soil after the second application chlorpyrifos residues were 0.21 and 0.46 mg kg^?1 and cypermethrin residues 0.15 and 0.36 mg kg^?1. At harvest, both pesticides showed residues below the LOQ. Based on this study, application of cypermethrin towards harvest may be avoided whereas chlorpyrifos can be applied with 22 days PHI.     

Residue behaviour and safety evaluation of fenaminstrobin in peanut field ecosystems

A rapid, sensitive, and selective method using a quick, easy, cheap, effective, rugged, and safe procedure in combination with high-performance liquid chromatography and tandem mass spectrometry was developed for the analysis of fenaminstrobin in peanut and soil. The average recoveries in all samples fall within 88.1%–10%, having relative standard deviations of 2.5%–14%. The limits of quantitation of fenaminstrobin in peanut shell, peanut kernels, peanut plant, and soil were 0.005, 0.004, 0.01, and 0.002 mg kg^?1, respectively. The field trial results show that the half-lives of fenaminstrobin in peanut plant and soil are 1.3–10 and 5.5–20 days, respectively. Residues in peanut kernels were found to be present at <0.004 mg kg^?1 levels, based on good agricultural practices recommended by the manufacturer. The risk posed by fenaminstrobin exposure at the recommended dosage is negligible to humans, depending on the risk quotient.     

Analysis of Nanafrocin in Foodstuffs of Animal Origin by LC–MS–MS

A new, rapid, and efficient method, multiple reaction monitoring liquid chromatography–tandem mass spectrometry, has been developed for analysis of nanafrocin in foodstuffs of animal origin. The researchers used a C₁₈ stationary phase coupled with triple-quadrupole tandem mass spectrometry in negative-electrospray mode. The limits of detection (LOD) and quantification (LOQ) were 0.005 and 0.01 mg kg^?1, respectively, in the matrixes. Detector response was found to be a linear function of concentration over the range 0.005–0.1 mg kg^?1 in each matrix. Mean overall recovery (n = 10) of nanafrocin varied from 71 to 101%. The results show that identification and quantification of nanafrocin residues in foodstuffs of animal origin can be successfully achieved by use of the proposed LC–MS–MS method.     

MSPD–GC–MS–MS Determination of Residues of 15 Organic Nitrogen-Containing Pesticides in Vegetables

A novel and simple method for determination of 15 organic nitrogen-containing pesticides in vegetables using matrix solid-phase dispersion (MSPD) coupled with gas chromatography tandem mass spectrometry (GC–MS–MS) has been developed. The efficiencies of different sorbents (florisil, silicone, neutral alumina) for the MSPD were compared. Mean recoveries of the method using neutral alumina varied from 73.26 to 111.83% with relative standard deviations of 0.79–15.33% in the concentration range of 0.01, 0.02 and 0.05 mg kg^?1. The limits of detection were typically in the 0.0007–0.0320 mg kg^?1 range, which were 10–100 times lower than the maximum residue levels established by the European Union. This method was applied to residue detection in vegetables, in which organic nitrogen-containing compounds were detected at low concentrations.