Behavior of trifloxystrobin and propineb as combination product in tomato (Solanum lycopersicum) and their risk assessment for human health.

Fungicides have their own unique characteristics and modes of action; a combination formulation [combination product (combi product)] of trifloxystrobin and propineb was applied to tomatoes for their dissipation kinetics and to ensure consumer safety. The combi product was applied at a 10-day interval with standard (61.25 + 1072.75 g a.i. ha-1 ) and double (122.5 + 2145.50 g a.i. ha-1 ) doses. The efficient analytical method was established using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach followed by LC-MS. The maximum residue levels of 0.15 and 0.35 mg kg-1 of trifloxystrobin were detected in tomato fruits immediately after application at standard and double doses, respectively. The corresponding levels of propineb as carbon disulfide were 0.47 and 0.90 mg kg-1 , respectively. Considering trifloxystrobin (0.7 mg kg-1 ) codex maximum residue limit and propineb as dithiocarbamate (3.0 mg kg-1 ) European Commission maximum residue limit in tomato, a pre-harvest interval of 1 day can be proposed. The anticipated residue contributions of both fungicides were far less than the acceptable daily intake. The targeted hazard quotient and hazard index were also less than 1 for both fungicides. Furthermore, the theoretical maximum residue contribution was less than its maximum permissible intake, which indicates that the consumption of tomatoes containing the measured value of each fungicide residue could not pose any health risks.

Method validation, dissipation and residue status of fluopicolide and fosetyl-aluminium in citrus using a rapid extraction method coupled with ultra-performance liquid chromatography-tandem mass spectrometry.

The dissipation and residue status of a combination of fluopicolide and fosetyl-aluminium (fosetyl-Al) in citrus were evaluated in an experimental field. An efficient and sensitive liquid chromatography-tandem mass spectrometry, with rapid extraction, was carried out according to the SANTE guidelines. During the method validation, the recovery was within the range of 106.1-117.5, 94.4-115 and 85.4-109.5%, for fluopicolide, its metabolite 2,6-dichlorobenzamide and fosetyl-Al, respectively, with a relative standard deviation (RSD) of 0.3-10.6%. As a result, accuracy and precision at the spiking concentrations of 0.01, 0.05 and 0.10 mg/kg in citrus were within the acceptable range of 70-120% with an RSD of 20%. The amount of the deposits of fluopicolide, 2,6-dichlorobenzamide and fosetyl-Al was less than the limit of quantification (LOQ) at 0.01 mg/kg at 0 day, adhering to the application in standard [1.77 + 2.66 g of active ingredient (a.i.)/L] and double (3.54 + 5.32 g a.i./L) doses. The present study proposes that the utilisation of fluopicolide and fosetyl-Al in citrus and the soil may not pose a health or environmental hazard provided that good agricultural practices are followed.

Development, validation and evaluation of matrix effect of a QuEChERS-based multiresidue method with low temperature dispersive clean-up for analysis of 104 pesticides in cumin (Cuminum cyminum) by LC-MS/MS.

BACKGROUND: Until now, there is no method available for analysis of pesticide residues in complex matrices like spices. Therefore, there is an urgent need to develop and validate a QuEChERS-based method for the estimation of 104 pesticides in cumin seed. RESULTS: Samples were spiked for 109 pesticides at concentrations of 0.1, 0.5 and 1.0 mg kg-1 . Of these 104 pesticides were recovered. At 0.1, 0.5 and 0.1 mg kg-1 , recoveries ranged from 71% to 108% when compared with matrix matched standards. Seventeen pesticides showed higher or lower recoveries than acceptable range (70-120%) when quantified using solvent standards showing significant matrix effect (ME) (≥ ±20%) even after 20× dilution. However, for the other pesticides ME was significantly eliminated on dilution. The recovery percentage improved for all pesticides on quantitation with matrix matched standards when compared with solvent standards. For pesticides with lower European Union (EU) maximum residue limits (MRLs), an experiment at lower spiking concentrations of 0.01 and 0.05 mg kg-1 with lower dilutions (8×) reveals that almost all pesticides with lower EU MRLs (0.02 and 0.05 mg kg-1 ) showed recoveries in the range 74-124% and relative standard deviation (RSD) less than 20%. CONCLUSION: Theoretical limit of quantitation (LOQ) is proposed which ranged from 0.01 to 0.18 mg kg-1 for matrix matched standards. An LOQ of 0.01 mg kg-1 was easily achieved for the pesticides with lower EU MRLs with lower dilutions (8×) with exception of fipronil for which this can be achieved without dilution provided matrix matched standards are used. The method can be extended to other spices. © 2021 Society of Chemical Industry.

Development and validation of multiresidue analytical method in cotton and groundnut oil for 87 pesticides using low temperature and dispersive cleanup on gas chromatography and liquid chromatography-tandem mass spectrometry.

A method was developed and validated for the analysis of 87 pesticides in cotton and groundnut oil by GC with ECD and FPD detectors and LC-MS/MS. The extraction procedure based on QuEChERS followed by low-temperature freezing and dispersive cleanup steps was validated in two oil matrices for 87 pesticides of different classes. Linearity, expressed as coefficient of variation, was within the acceptable range. Of those tested, 77-83 and 77-89% pesticides showed recoveries within the acceptable range of 70-120% on LC-MS/MS in cottonseed oil and groundnut oil, respectively, at different spiking levels. In case of GC analysis, 63-65 and 53-82% pesticides showed recoveries within the acceptable range of 70-120% on GC in cottonseed oil and groundnut oil, respectively, at different spiking levels. The exceptions to these recoveries were the few organochlorines which consistently gave lower recoveries. Recovery factors can be employed while analysing these pesticides by this method as the results obtained were consistent in both oils. RSD was less than 20% for most of the pesticides. The calculated limit of quantitation (LOQ) for most of the pesticides satisfies the maximum residue level (MRL) requirements as per European Union (EU) guidelines and Food Safety and Standards Authority of India (FSSAI).

Validation of a QuEChERS-based gas chromatographic method for analysis of pesticide residues in Cassia angustifolia (senna).

A simple multi-residue method based on modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach was established for the determination of 17 organochlorine (OC), 15 organophosphorous (OP) and 7 synthetic pyrethroid (SP) pesticides in an economically important medicinal plant of India, Senna (Cassia angustifolia), by gas chromatography coupled to electron capture and flame thermionic detectors (GC/ECD/FTD) and confirmation of residues was done on gas chromatograph coupled with mass spectrometry (GC-MS). The developed method was validated by testing the following parameters: linearity, limit of detection (LOD), limit of quantification (LOQ), matrix effect, accuracy-precision and measurement uncertainty; the validation study clearly demonstrated the suitability of the method for its intended application. All pesticides showed good linearity in the range 0.01-1.0 µg mL(-1) for OCs and OPs and 0.05-2.5 µg mL(-1) for SPs with correlation coefficients higher than 0.98. The method gave good recoveries for most of the pesticides (70-120%) with intra-day and inter-day precision < 20% in most of the cases. The limits of detection varied from 0.003 to 0.03 mg kg(-1), and the LOQs were determined as 0.01-0.049 mg kg(-1). The expanded uncertainties were <30%, which was distinctively less than a maximum default value of ±50%. The proposed method was successfully applied to determine pesticide residues in 12 commercial market samples obtained from different locations in India.

Multilocation field trials for risk assessment of a combination fungicide Fluopicolide + Propamocarb in tomato.

Dissipation kinetics of two systemic fungicides, namely fluopicolide and propamocarb used as a combination formulation (Infinito 68.75 SC), were studied on tomato at four different locations by the All India Network Project on Pesticide Residues to recommend their pre-harvest interval (PHI) and to propose the maximum residue limits (MRL) for the two fungicides based on chronic hazard exposure assessment. The combination fungicide was sprayed thrice at the recommended dosage of 93.75 g a.i./ha fluopicolide and 937.50 g a.i./ha propamocarb as well as at double the recommended dosage of 187.50 g a.i./ha fluopicolide and 1875.0 g a.i./ha propamocarb on tomato crops and the residues were monitored periodically by GC-MS. The fungicides dissipated to below the limit of quantification (LOQ) within 10 to 15 days, with a half-life of 2-4 days for fluopicolide and 1-2 days for propamocarb. Taking into consideration the MRLs of codex and calculations made using the method of MRL fixation of the Food Safety and Standard Authority of India (FSSAI) as well as the Organization for Economic Co-operation and Development (OECD) calculator, MRL of 5 mg/kg is proposed for fluopicolide and 15 mg/kg for propamocarb, following critical exposure of the commodity considering PHI of 1 day.

Persistence and risk assessment of spiromesifen on tomato in India: a multilocational study.

Supervised field trials were conducted at four different agro-climatic locations of India to evaluate the dissipation pattern and risk assessment of spiromesifen on tomato. Spiromesifen 240 SC was sprayed on tomato at 150 and 300 g a.i. ha(-1). Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10 and 15 days after treatment and soil at 15 days after treatment. Quantification of residues was done on gas chromatograph-mass spectrophotometer in selective ion monitoring mode in the mass range of 271-274 (m/z). The limit of quantification of the method was found to be 0.05 mg kg(-1), while the limit of determination was 0.015 mg kg(-1). Residues were found below the LOQ of 0.05 mg kg(-1) in 10 days at both the doses of application at all the locations. Spiromesifen dissipated with a half-life of 0.93-1.38 days at the recommended rate of application and 1.04-1.34 days at the double the rate of application. Residues of spiromesifen in soil were detectable level (<0.05 mg kg(-1)) after 15 days of treatment. A preharvest interval (PHI) of 1 day has been recommended on tomato on the basis of data generated under All India Network Project on Pesticide Residues. Spiromesifen 240 SC has been registered for its use on tomato by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of spiromesifen on tomato has been fixed by Food Safety Standard Authority of India, Ministry of Health and Family Welfare, Government of India as 0.3 µg/g after its risk assessment.

Dissipation kinetics of co-formulation with two herbicides, clodinafop-propargyl and oxyfluorfen, in/on onion (Allium cepa) samples.

Supervised field trail on dissipation of co-formulation with herbicides clodinafop-propargyl and oxyfluorfen in spring onion showed similar pattern of dissipation during two different seasons. Residues of clodinafop-propargyl reached ≤ limit of quantitation (LOQ, 0.05 mg kg-1) on 3rd day after application at both standard and double dose during both the seasons. Oxyfluorfen residues followed first-order kinetics in both the doses during first season with half-life of 0.81 to 3.14 days. The residues of clodinafop-propargyl were detected in soil at both the doses during first season. However, residues were ≤ LOQ (0.05 mg kg-1) during second season. The residues of oxyfluorfen were detected only in double dose during first season in soil. In all other cases and in onion bulb, residues were ≤ LOQ (0.05 mg kg-1) at the time of harvest. As the residues were either ≤ LOQ (0.05 mg kg-1) on 3rd day or have a half-life of 3.14 days, the co-formulation can be used safely, provided a pre harvest interval (PHI) of 3 days is followed. On the basis of maximum residue limits (MRLs) in other commodities and from the data of present study, a default MRL of 0.05 mg kg-1 is proposed for both the pesticides.

Analytical method development, validation and study on behaviour of ipfencarbazone in paddy (rice).

Supervised field trial was conducted to study persistence of a pre-emergent herbicide, ipfencarbazone (25% SC) on rice crop. Single application of two different doses, 156.25 g a.i.ha-1/625 mL formulationha-1 and 312.50 g a.i.ha-1/1250 mL formulationha-1, was applied. Method was validated to analyse ipfencarbazone in rice samples (leaf/plant, grain, straw and husk) and in soil. Initial accumulation of ipfencarbazone in rice plants was 6.72 and 14.71 mg kg-1 in standard and double dose, respectively. The residues decreased linearly with r2 values of 0.92 and 0.98 in different doses and reached below limit of quantitation (LOQ) of 0.01 µg kg-1 (for rice plant/leaf) and 0.05 µg kg-1 (for rice grain, husk, straw) on 30th and 97th (harvest) day respectively after application in both the doses. An average half-life of ipfencarbazone was approximately 4 days. Less than LOQ levels at harvest and short half-life suggest that the use of ipfencarbazone is safe, provided good agricultural practices (GAP) are followed. The data can be used by regulatory authorities like Food Safety and Standards Authority of India (FSSAI) and CODEX for establishing maximum residue limits (MRLs) of ipfencarbazone.

Persistence evaluation of fluopyram + tebuconazole residues on mango and pomegranate and their risk assessment.

The persistence of combination formulation of fluopyram 200 + tebuconazole 200-400 SC was evaluated across different agro-climates in India for the management of fungal diseases in two commercially important fruit crops, mango and pomegranate. The residues were extracted using quick easy cheap effective rugged and safe (QuEChERS) method and quantification was done on liquid chromatography-tandem mass spectrometry (LC-MS/MS). The fungicide degradation followed 1st-order kinetics and the half-lives were 2.9-6.4 days for mango, and 3.5-7.4 days for pomegranate for both the fungicides. On the basis of Organisation for Economic Co-operation and Development (OECD) maximum residue limit (MRL) calculation, 1.0 mg kg-1 MRL was obtained for fluopyram while for tebuconazole, it was 0.5 mg kg-1 on mango, at the pre-harvest interval (PHI) of 5 days. For pomegranate, the respective MRLs were 1.0 mg kg-1 and 0.7 mg kg-1 at PHI of 7 days. The dietary risk assessment study indicated that % acceptable daily intake (% ADI) and % acute reference dose (% ARfD) were much lower than 100; thus, the application of fluopyram and tebuconazole on mango and pomegranate is unlikely to present public health concern.

Dissipation of flubendiamide in/on Brinjal (Solanum melongena) fruits.

A field experiment was conducted at Anand Agricultural University, Anand during Sept-Dec, 2009 to study the rate of degradation of flubendiamide in/on brinjal fruits following foliar application of Fame 480 SC at 90 (standard dose) and 180 (double dose) g a.i. ha( -1). The residues estimated using HPLC revealed persistence of flubendiamide in/on brinjal till 3rd and 7th day after the last spray at standard and double dose, respectively. The residues of flubendiamamde were reported as parent compound, and no desiodo metabolite was detected. The initial deposits of 0.17 and 0.42 µg g( -1) in/on brinjal fruits reached below determination level of 0.05 µg g( -1) on the 5th and 10th day at standard and double dose, respectively. The half life of flubendiamide on brinjal fruits ranged from 2.68 to 2.55 days. Soil samples analyzed on the 15th day after the last spray revealed residues at below determination level (0.05 µg g( -1)) at either dose of application.

Validation of a QuEChERS-Based Method for the Estimation of Afidopyropen in Brinjal (Solanum Melongena L.) and Soil.

BACKGROUND: Afidopyropen is a recently introduced insecticide that provides effective control of insect pests in vegetable crops, including brinjal. Field applications of this insecticide can often result in accumulation of residues in brinjal fruits, leaves, and soil at harvest, which might be a concern for food and environmental safety. This demands an appropriate method for analysis of the residues of this insecticide in these matrices to facilitate residue monitoring and safety compliance checks. OBJECTIVE: The study aims to validate a quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based method for estimation of afidopyropen in/on brinjal leaf, fruit, and soil by ultrahigh-performance liquid chromatograph-tandem mass spectrometer (LC-MS/MS). METHODS: The brinjal fruit, leaf, and soil samples were extracted by an optimized QuEChERS workflow-based sample preparation method and analyzed by LC-MS/MS. RESULTS: Linearity [with coefficient of determination (R2) >0.99] was obtained in calibration curves drawn from standards prepared in the matrix and neat solvent. Although negligible matrix effects were noted in fruit and soil, ion suppression was significant in the leaf matrix (71.6%). The recoveries were within the acceptable range of 70-120%, with relative SD ≤20%. In all cases, Horwitz ratio values were within the acceptable range of 0.3-1.3, indicating satisfactory repeatability. The LOQs were 0.004, 0.001, and 0.001 mg/kg for brinjal fruit, leaf, and soil, respectively. At the spiking concentrations of 0.01, 0.05, and 0.1 mg/kg, the estimated measurement uncertainty was <50% for all matrices. CONCLUSIONS: Because of its satisfactory precision and accuracy, the proposed method can be extended for estimation of afidopyropen in other vegetables for evaluating maximum residue limit compliance. HIGHLIGHTS: The study reports an optimized method for high-throughput residue analysis of afidopyropen in/on brinjal leaf, fruit, and soil. The accuracy, precision, selectivity, and sensitivity of the method comply with the regulatory requirements.

Correction to: Behaviour and risk assessment of fluopyram and its metabolite in cucumber (Cucumis sativus) fruit and in soil.

Unfortunately, the original publication of this paper contains a mistake. The correct name of the 3rd Author is Sunny H. Patel. The original article has been corrected.

Behaviour and risk assessment of fluopyram and its metabolite in cucumber (Cucumis sativus) fruit and in soil.

A field experiment was conducted to estimate residue persistence of fluopyram and its metabolite benzamide in cucumber fruits and soil and their risk assessment in humans and soil environment. Fluopyram (Kafka, 400 SC) was applied as soil drench twice at the interval of 15 days at the rate of 250 (standard dose) and 500 (double dose) g a.i. ha-1 (active ingredient per hectare). Cucumber fruits were collected at 0 (1 h), 1, 3, 5, 7, 10, 15, 20, 30, 40 and 50 days after second application. Soil samples were collected on 15th day after second application. Drench application resulted in detection of residues on the third day in standard dose at the levels of 0.056 mg kg-1 in cucumber fruit. The residue level increased until 20 days reaching 0.092 mg kg-1 followed by decrease to 0.068 mg kg-1 on 30th day after application. In double dose, the residues started accumulating from 0 day with initial levels of 0.093 mg kg-1 and persisted until 30th day. The levels varied between 0.123 and 0.184 mg kg-1 until 15th day of application followed by decrease to 0.127 mg kg-1 by 30th day. The residues reached below determination level (< 0.05 mg kg-1) on 40th day in both the doses after second application. The residue of metabolite benzamide was below determination level (< 0.05 mg kg-1) at both the doses. Hazard quotient (HQ) for residues levels at 15th and 30th day was less than one (HQ < 1). Hence, a pre-harvest interval of 15 days is suggested. Present data can be used to establish maximum residue limit (MRL) in India. The residue of fluopyram in soil on 15th day and the data on soil adsorption coefficient of fluopyram from literature suggests moderate mobility of fluopyram in soil. However, residues of metabolite of benzamide were not detected in soil. Further studies on translocation of fluopyram in soil over the time can be conducted for better understanding of environmental risk. To our knowledge, this is the first report on residue levels of fluopyram in any crop when applied as soil drench.

Validation, residue analysis, and risk assessment of fipronil and flonicamid in cotton (Gossypium sp.) samples and soil.

Cotton crop is highly susceptible to attack by sucking pests. Being an important oilseed and feed crop, it is essential to monitor the pesticides and ensure health protection at consumer level. Therefore, a method was validated to estimate fipronil and flonicamid in various cotton samples and risk assessment was performed. Contamination of oil in the extracts from the various oil seeds and cake samples is a major problem as this oil contaminates the column and interferes with the detection of pesticides. The present manuscript for the first time describes successful analysis of the pesticides from various cotton samples including cotton oil, seed, and cake. Quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based methods were validated for estimation of fipronil and flonicamid in cotton samples and in soil by LC-MS/MS. Recoveries were within the acceptable range of 70-120% with relative standard deviation ≤ 20% and HorRat values < 0.3-1.3. R2 was > 0.99. Matrix effects of 150 and 13.5% were observed for fipronil and flonicamid, respectively, in cotton leaves. Limits of quantitation (LOQs) were in the range of 0.0004 to 0.004 mg kg-1 for fipronil and flonicamid. Cotton samples collected from a field study at different locations were analyzed. Half-life ranged from 2.2 to 5.8 for fipronil and 4.6 to 7.0 days for flonicamid. A pre-harvest interval of 33 days is suggested. The risk assessment studies at maximum residue level values showed HQ < 1 at pre-harvest interval (PHI). The methods being short and easy can be extended to estimate more types of pesticides in different oilseeds. Following a PHI of 33 days, fipronil and flonicamid can be used on cotton at standard dose. As the levels of fipronil and flonicamid were below determination limit in all the soils, the environmental risk is negligible.

Evaluation of Matrix Effects in Multiresidue Analysis of Pesticide Residues in Vegetables and Spices by LC-MS/MS.

The study was conducted to investigate matrix interferences using QuEChERS sample preparation to understand whether the dilution of matrix and/or the grouping of commodities can eliminate the need for selective individual matrix-matched standards in LC with tandem MS (MS/MS) analysis, and whether the calibration graph based on only one matrix can be used for quantification in the other matrixes. Matrix effects (MEs) were studied by comparing the slopes of calibration curves of the matrix-matched standards (diluted with mobile phase) vis-à-vis the solvent-based standards. The present study showed that MEs were dependent on the nature of both the commodity and the analyte. Among the test matrixes, the highest variability in ME was recorded in capsicum. Most of the pesticides showed signal suppression in tomato, capsicum, and cumin matrixes. In brinjal matrix, the signal of most of the pesticides showed slight enhancement. Due to the similar nature of the MEs in tomato and capsicum, these two commodities can be grouped together. Considering analyte variability, acetamiprid, 3-hydroxy carbofuran, dichlorvos, dimethoate, and spinosyn A and D showed no significant ME (≤20%) in tomato. Very high MEs (2360.9 and 1250.8%) were observed for quizalofop-p-tefuryl and tebuconazole, respectively. To check the effect of dilution in minimizing the ME, cucumber and brinjal matrixes were diluted 10×, and calibration curves were drawn with five concentration levels. It was found that about 60% of the total analyzed pesticides showed MEs ≤20%. In cumin, MEs ranged from -5.3% for triazophos to 661% for thiacloprid. Most of the pesticides showed recoveries in the acceptable range of 70-130% with calibration curves from both matrixes. To compensate for MEs, it is suggested that (1) tomato and capsicum matrixes, which show similar trends, can be grouped together; and (2) cucumber matrix, when diluted 10×, can be used to prepare calibration curves for the quantification of pesticides in various fruiting and cucurbit vegetable matrixes by LC-MS/MS.

Residue decline and risk assessment of fluopyram + tebuconazole (400SC) in/on onion (Allium cepa).

A method was validated for estimating fluopyram and tebuconazole in onion on LC-MS/MS using dispersive QuEChERS. Three sprays of a combination fungicide fluopyram + tebuconazole (Luna experience, 400 SC) were applied @ 75 + 75 and 150 + 150 g a.i. ha-1 at an interval of 10 days on onion using Knapsack sprayer. First spray was made at bulb setting stage. Spring onion samples were drawn at 0 (1 h), 1, 3, 5, 7, 10, 15, and 20 days and matured onion bulb at harvest (52 days) after the last spray. Soil samples were also drawn at harvest. Foliar application of the combination product resulted in 1.14 and 2.86 mg kg-1 fluopyram residues on spring onion at standard and double dose, respectively, one hour after the last application. The levels of fluopyram residues gradually declined and recorded 0.25 and 0.58 mg kg-1 on 20th day of application with half-lives of 8.8 and 9.1 days at standard and double dose, respectively. For tebuconazole, the corresponding residues observed after 1 h (0 day) of application were 0.92 and 2.29 mg kg-1. The levels declined gradually to 0.12 and 0.33 mg kg-1 on 20th days with half-life of 6.7 to 7.7 days at standard and double dose, respectively. Here, we are proposing a pre-harvest interval of 7 day for fluopyram and tebuconazole in spring onion when applied at 75 + 75 g a.i. ha-1 (400 SC). Risk assessment was done by calculating hazard quotient and by comparing theoretical maximum residue intake (TMRI) with maximum permissible intake (MPI). In all the cases, results of the study showed that HQ (Hazard Quotient) ≤1 and TMDI < MPI. Hence, the use of this combination product can be recommended with pre harvest interval of 7 days. The data can be used in establishing MRLs (maximum residue limits) for spring onion after considering multilocation trials.