Quantification, dissipation behavior and risk assessment of ethion in green pea by gas chromatography-electron capture detector

Simultaneous determination of four fungicide residues in figs using liquid chromatography tandem mass spectrometry

Dissipative behavior and final residue levels of difenoconazole, prochloraz, propiconazole, and pyraclostrobin in figs were investigated using field trials and laboratory assays. A three-factor, three-level orthogonal test was designed to optimize the pretreatment conditions of the method. A method was established using high-performance liquid chromatography tandem mass spectrometry for the determination of difenoconazole, prochloraz, propiconazole, and pyraclostrobin residues in figs. The limit of quantification for all four targets in figs was 0.002 mg/kg. Difenoconazole, prochloraz, propiconazole, and pyraclostrobin are readily digestible pesticides in figs with half-lives of 6.4, 6.2, 4.8, and 7.9 days, respectively. Residues of difenoconazole, prochloraz, propiconazole, and pyraclostrobin in figs were below the European Union established residue levels of 0.1, 0.03, 0.01, and 0.02 mg/kg, respectively, at day 7 after application. Pyraclostrobin, propiconazole, difenoconazole, and prochloraz were applied twice at doses of 75, 125, 150, and 200 mg a.i./kg at 7-day intervals, and the residues of the four fungicides in figs were acceptable 7 days after the last application. Therefore, the safety interval can be set at 7 days for 70% difenoconazole-prochloraz wettable powder and 40% pyraclostrobin-propiconazole aqueous emulsion according to the protocol.

Spectroscopic characterization and pharmacokinetic evaluation of amorphous solid dispersions of glibenclamide for bioavailability enhancement in Wistar rats

Oral bioavailability of glibenclamide (Glb) was appreciably improved by the formation of an amorphous solid dispersion with Poloxamer-188 (P-188). Poloxamer-188 substantially enhanced the solubility and thereby the dissolution rate of the biopharmaceutics classification system (BCS) class II drug Glb and simultaneously exhibited a better stabilizing effect of the amorphous solid dispersion prepared by the solvent evaporation method. The physical state of the dispersed Glb in the polymeric matrix was characterized by differential scanning calorimetry, X-ray diffraction, scanning electron microscope and Fourier transform infrared studies. In vitro drug release in buffer (pH 7.2) revealed that the amorphous solid dispersion at a Glb-P-188 ratio of 1:6 (SDE4) improved the dissolution of Glb by 90% within 3 h. A pharmacokinetic study of the solid dispersion formulation SDE4 in Wistar rats showed that the oral bioavailability of the drug was greatly increased as compared with the market tablet formulation, Daonil®. The formulation SDE4 resulted in an AUC0-24h ~2-fold higher. The SDE4 formulation was found to be stable during the study period of 6 months.

Impact of different decontamination methods on the reduction of spiromesifen residue in chilli fruits

Chilli is an indispensable food item in the daily life of humans but it is affected by many insects, so various pesticides, including spiromesifen, are applied to chilli crops to protect this crop from insect infestation. However, the use of pesticides poses environmental and health issues. These issues have raised the demand for pesticide-free chillies among consumers. The primary aim of this study was to assess the efficacy of various decontamination methods in removing spiromesifen residues from chilli fruits. A randomized block design was employed to conduct a supervised field experiment at the Rajasthan Agricultural Research Institute in Durgapura, Jaipur, India. The samples of chillies treated with pesticides are subjected to seven different homemade techniques. The samples were extracted using the QuEChERS method, known for its efficiency, affordability, simplicity, robustness, and safety. The analysis of spiromesifen residues was conducted using gas chromatography (GC) equipped with an electron capture detector (ECD), and the results were verified using gas chromatography-mass spectrometry (GC-MS). Out of several decontamination methods, the lukewarm water treatment was more effective than any other decontamination method, which led to the highest elimination of spiromesifen residue, whereas rinsing with tap water eliminates the least amount of spiromesifen residue. So, the lukewarm water treatment is a safe, cost-effective, and eco-friendly approach to remove spiromesifen residues from Chilli.

Assessment of flusilazole residues on apples: Detection, quantification and health risk implications

Apple, a major fruit of temperate Himalayas, is sprayed with chemical pesticides around 12 times during the cropping season. Various systemic and contact fungicides are applied for the management of major diseases. In order to manage disease, flusilazole 40 EC is frequently used. However, excessive chemical application has been found to be detrimental for consumer safety. Keeping in view consumer safety, risk assessment, the half-life and waiting period for flusilazole 40 EC were evaluated on the Red Velox variety of apple. The QuEChERS (quick, easy, cheap, effective, rugged and safe) method and high-performance liquid chromatography were adapted for sample processing and analysis, respectively. The recovery percentages of flusilazole at three fortification levels (0.04, 0.09 and 0.50 mg kg-1) were 98.85, 99.83 and 98.98%, respectively. Flusilazole at the recommended dose (80 g a.i. ha-1) left an initial deposit of 0.733 mg kg-1, which dissipated by 93.45% in 60 days and was non-detectable beyond this period. Meanwhile flusilazole at double the recommended dose (160 g a.i. ha-1) left an initial deposit of 0.913 mg kg-1, which dissipated by 93.43% in 70 days and was non-detectable beyond this period. Based on the maximum residue limit of 0.3 mg kg-1 as prescribed by the Codex Alimentarius Commission, a waiting period of 28.74 and 46.03 days was recorded for single and double doses, respectively. Moreover, in order to assess the consumer risk, theoretical maximum residue contributions (TMRCs) were derived using flusilazole residues (average and maximum) recorded at various time intervals and compared with the maximum permissible intake, which was found to be 0.42 mg per person per day. Based on the average per capita daily consumption of 6.76 g apple in India, the TMRC values were computed. Although the values of TMRC decreased below maximum permissible intake at the first day after application, indicating minimal consumer health risks, fruits sprayed with a double dose of flusilazole carried the risk even up to the tenth day after flusilazole application. The results of the present study will be valuable for safe and timely use of flusilazole on apple.

Monitoring and method validation of organophosphorus/organochlorine pesticide residues in vegetables and fruits by gas chromatography

In this study, an analytical method was developed and validated for the assessment of pesticide residues in commonly consumed vegetables and fruits. Fresh samples of apple, green peas, tomatoes, and cucumbers were processed and subjected to analysis using a modified QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction technique. Subsequently, quantification of pesticide residues was conducted utilizing gas chromatography (GC)-electron capture detector. Extraction and cleanup parameters were meticulously optimized, resulting in a modification of the original QuEChERS method. This modification aimed to reduce solvent consumption, making the study more environmentally friendly. The developed method was validated in terms of selectivity, specificity, linearity, precision, and accuracy by following the SANTE guidelines. Calibration curves showed good linearity (r > 0.99) within the test range. Precision was evaluated by intra- and inter-day experiments with an acceptable relative standard deviation (<20.0%). Recovery was assessed at the limit of quantification level and was observed to fall within the range of 70%-120%, with relative standard deviations below 5.45%. The validated method presented here can be applied to analyze pesticide residues in various other vegetables, fruits, and cereals. It is essential for ongoing monitoring of pesticide residues to ensure public safety.

Dissipation kinetics, residue determination and consumer risk assessment of acephate on green pea by gas chromatography-electron capture detector

The present study on "acephate persistence on green pea" was conducted in SKUAST-Kashmir. The study aimed to determine the persistence, dissipation kinetics and waiting period of acephate on green pea. Acephate was sprayed at 75% soluble powder (SP) at 560 g a.i.ha-1 at the fruiting stage followed by another application at a 10 day interval. A rapid and accurate method (quick, easy, cheap, effective, rugged and safe, QuEChERS) was used for extraction and the residue was determined by gas chromatography-electron capture detection on a CPSIL-8CB capillary column (0.25um film thickness, 0.25 mm i.d, 30 m length). At the fortification levels of 0.05, 0.1 and 0.5 mg kg-1 , the percentage recovery of acephate on green pea was found in the range of 71-107%. The initial deposit of green pea was estimated to be 0.37 mg kg-1 . At the indicated dose, the residue of acephate on green pea dissipated below the limit of quantification of 0.05 mg kg-1 after 10 days. Acephate degradation was quick in green pea, with a half-life of 4.07 days. For safe eating of green peas, a 10 day waiting period is recommended. The gas chromatography-electron capture detection technique was validated by following the SANTE standards.

The effect of different decontamination processes on the residues of fipronil and its metabolites in chili fruits (Capsicum annuum L.)

Fipronil is a broad-spectrum phenyl pyrazole insecticide that has a high degree of environmental toxicity. Commonly available chilies in the market are treated with fipronil insecticides. Demand for insecticide-free chili has thus been increasing globally. This needs various sustainable and economical methods to remove insecticides from chilies. The present study examined the effectiveness of several cleaning methods to remove pesticide residues in chili fruits. A supervised field trial was conducted in randomized block design at Rajasthan Agricultural Research Institute, Durgapura, Jaipur, India. Chili samples were subjected to seven different household methods. The samples were extracted using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. The residues were analyzed using a gas chromatograph-electron capture detector and confirmed by GC-MS. Of the seven methods, the acetic acid treatment removes the maximum residue effect of fipronil and its metabolites (desulfinyl [MB046513]), sulfide (MB045950), and sulfone (MB046136) on chili fruits. By contrast, the tap water treatment was the least effective. The Food Safety and Standards Authority of India (FSSAI) have set the maximum residue limit value of 0.001 mg kg-1 for fipronil on green chili.

Recent bioanalytical methods for the isolation of bioactive natural products from genus Codonopsis

INTRODUCTION

Chromatography and spectroscopy are nowadays well-validated techniques allowing to isolate and purify different class of natural products from the genus Codonopsis. Several categories of phytochemicals with drug like properties have been selectively extracted, isolated, characterised by this methodology.

OBJECTIVES

The present review aims to provide up-to-date and comprehensive information on the chromatography, phytochemistry and pharmacology of natural products of Codonopsis with an emphasis on the search for natural products having various biological activities and the semi-synthetic derivatives of bioactive ones and to highlight current gaps in knowledge.

MATERIALS AND METHODS

A literature search was performed in the SciFinder Scholar, PubMed, Medline, and Scopus databases.

RESULTS

During the period covered in this review, several classes of compounds have been reported from genus Codonopsis. Codonopsis pilosula and Codonopsis lanceolata are the most popular in the genus especially as per phytochemical and bioactive studies. Phytochemical investigation demonstrates that Codonopsis species contain mainly xanthones, flavonoids, alkaloids, polyacetylenes, phenylpropanoids, triterpenoids and polysaccharides, which contribute to numerous bioactivities. The major bioactive compounds isolated were used for semi-synthetic modification to increase the chance to discover lead compound.

CONCLUSIONS

It can be concluded that genus Codonopsis has been used as traditional medicines and food materials around the world over years due to chemical constituents with diverse structural types, exhibiting extensive pharmacological activities in immune system, blood system, cardiovascular system, central nervous system, digestive system, and so forth, with almost no obvious toxicity and side effect. Therefore, Codonopsis can be used as a promising ethnopharmacological plant source.

Dissipation kinetics, risk assessment, and waiting period of spiromesifen on chili fruits using gas chromatography-electron capture detector

A supervised field trial was designed in Rajasthan Agricultural Research Institute, Durgapura, Jaipur, Rajasthan, to assess the dissipation and persistence of spiromesifen in chili fruits. Spiromesifen (22.9% suspension concentrate) was sprayed two times at an interval of 10 days at the recommended dose (96 g. a.i. ha^-1 ) and double the recommended dose (192 g. a.i. ha^-1 ) with four replications. Sampling was done according to the planned interval of days after the second spray. Extraction and cleanup were performed using the modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and the spiromesifen residue was analyzed by GC-electron capture detector and confirmation performed using GC-MS. The average initial deposit of spiromesifen was 1.207 mg kg^-1 and 1.948 mg kg^-1 at the recommended and double the recommended dose, respectively. The half-life values of spiromesifen ranged between 2.7 and 3.2 days at the recommended and double the recommended dose. The safe waiting period was calculated for the respective doses and it was concluded that an average of 7 days is safe for picking. The FSSAI (Food Safety and Standards Authority of India) have set the maximum residue limit of 0.1 mg kg^-1 for spiromesifen in green chili. The theoretical maximum residue contribution value of spiromesifen was lower than the maximum permissible intake at both the applications on the 0th day. Hence, there will be no adverse effects on human health after consumption of green chilies.

Health Risk Assessment of Pesticide Residues in Drinking Water of Upper Jhelum Region in Kashmir Valley-India by GC-MS/MS

Globally growing demand for agricultural and farm foods has more or less become dependent on chemical pesticides to maintain the supply chain, which undoubtedly boosts agricultural production. However, pesticides not only impact the target pests but cause hazard to human health. Pesticides are ubiquitous and can be found in almost every component of the environment. They can therefore impair human and biota health when present over the threshold level. The present study assessed the concentration of commonly used pesticides for agricultural purposes but get mixed in different sources of water, as such fifteen sampling sites along the upper Jhelum basin of Kashmir valley were chosen. For the analysis, 60 water samples were obtained from different water sources. Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was used to determine pesticide residues in water samples. Pesticide residues from 10 of the 26 commonly used pesticides were detected in water samples. Difenoconazole had the highest concentration among the pesticides detected, with a mean concentration of 0.412 ± 0.424 μg/L ranging from 0.0 μg/L to 0.8196 μg/L. The target hazards quotient (THQ) was used to quantify the possible noncarcinogenic health risks associated with drinking pesticide-contaminated water. Only chlorpyrifos and quinalphos were detected >1 in RWS3 (1.6571), RWS4 (1.0285), RWS14 (1.2571), and RWS15 (1.2000) sample sites, implying that the drinking water poses a health risk to humans. Hence, pesticide hazards should be mitigated and rigorous monitoring is needed to reduce pesticide residues in drinking water.

Agrochemical Residues in Fish and Bivalves from Sepetiba Bay and Parnaiba River Delta, Brazil

Accumulation of pesticides has a harmful impact on the environment and human health. The main goal of this work was to develop a method to determine and quantify the residues of thirteen pesticides in edible fish and bivalves such as parati (Mugil curema), seabass (Centropomus ssp.), mullet (Mugil brasiliensis), clams (Anomalocardia brasiliana) and mussel (Mytilus galloprovincialis) collected from Sepetiba Bay and Parnaiba River Delta (Brazil) between 2019 and 2020. Matrix solid-phase dispersion (MSPD) was used for extraction and quantification through gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). The method was validated (linearity, accuracy and precision) for fatty fish (Salmo salar), lean fish (Mugil curema) and bivalves (Mytilus edulis). The survey found linear correlation coefficients (r) equal to or greater than 0.9 for almost all analytes. The relative standard deviations (RSD) of five replicates were less than 20% for almost all analytes at different concentrations in lean fish, fatty fish and bivalves. Most analytes showed satisfactory accuracy. Alachlor herbicide was found in samples of seabass, mussels, clams and parati with levels ranging between 0.55 to 420.39 μg kg-1 dw. Ethion was found in parati (maximum 211.22 μg kg-1 dw), mussels (15.1 μg kg-1 dw) and clams (maximum 44.50 μg kg-1 dw). Alachlor was found in clams (maximum 93.1 μg kg-1 dw), and bifenthrin was found in parati (maximum 43.4 μg kg-1 dw) and clams (maximum 42.21 μg kg-1 dw). The validated method was satisfactory for the determination of eleven pesticides in the fatty fish matrix, and thirteen pesticides in the samples of lean fish and bivalves. The presence of alachlor, ethion and bifenthrin stands out.

Risk assessment, development and validation of a GC-ECD-based method for the quantification of cypermethrin from green pea

The present work describes the persistence, dissipation behaviour, half-life, risk assessment and novel gas chromatography method for the residue estimation of cypermethrin in green pea by spraying cypermethrin 10EC at 50 g a.i. ha-1 at fruiting stage followed by another application at a 10 day interval. The sample extraction and cleanup was followed bya modified quick, easy, cheap, effective, rugged, and safe method, and the residues of cypermethrin were determined using a validated gas chromatography method. The initial deposits were found to be 1.21 mg kg-1 following the application of insecticide at 50 g a.i. ha-1 . Cypermethrin residues declined to below the detection limit of 0.05 mg kg-1 after 15 days at the recommended dosage. The half-life of cypermethrin was 2.66 days at 50 g a.i. ha-1 . For risk assessment studies, the waiting period of 15 days is recommended as safe for consumption for the insecticide. The GC-ECD method was validated according to the SANTE guidelines by various analytical parameters including linearity, accuracy, detection and quantification limits. The developed method is simple, selective and repeatable, and can be used for the standardization of pesticides on fruits and vegetables.

Dissipation and gas chromatographic method for the determination of profenofos residues in/on green pea and cucumber

Herein we report a novel, accurate and cost-effective gas chromatography method for the determination of average deposits of profenofos on green pea and cucumber following good agricultural practices. Additionally the risk assessment, dissipation and waiting period for profenofos were determined. The average initial deposits (2 h after spraying) of profenofos in/on green pea and cucumber were 3.41 and 3.62 mg kg-1 respectively following two applications at a 10 day interval of profenofos 50EC formulation. Profenofos residues on both of the substrates were below the detection limit of 0.05 mg kg-1 after 20 days at the recommended dosage. For risk assessment studies, the 20th day will be safe for consumers for consumption of green peas. The gas chromatography method was validated according to the SANTE guidelines using the various analytical parameters: linearity, accuracy, detection and quantification limits. The developed method is simple, selective and repeatable and can be extended for profenofos-based standardization of pesticide formulations for green pea/cucumber and their use as pesticides.

Simultaneous determination of dimethoate and its metabolite omethoate in curry leaf using LC-MS/MS and risk assessment

This study presents the method development, validation, and simultaneous determination of dimethoate and its metabolite omethoate in curry leaf. Samples were extracted following modified quick, easy, cheap, effective, rugged, and safe extraction protocol and analyzed using liquid chromatography-tandem mass spectrometry. The limit of quantification in the matrix was 0.005 μg g^-1 for dimethoate and omethoate. Extraction using acetonitrile recorded the average recoveries in the range of 82.25 to 112.97% for dimethoate and 85.57 to 107.22% for omethoate at 0.005, 0.025 and 0.050 μgg^-1 fortification levels and relative standard deviation less than 5%. Similarly, the relative standard deviation values for intraday (Repeatability) and interday (Reproducibility) tests were less than 15%. Dissipation kinetics of dimethoate 30% emulsifiable concentrate at 200 and 400 g a.i h^-1 recorded initial deposits of 5.20 and 10.05 μg g^-1 and 0.33 and 0.48 μg g^-1 for dimethoate and omethoate, respectively, and half-life of 3.07 and 3.34 days. The estimated hazard index value found more than one at a day after dimethoate application. It is not safe for consumer health to use curry leaves in the initial days after application. This article is protected by copyright. All rights reserved.

Method validation and simultaneous quantification of eight organochlorines/organophosphates in apple by gas chromatography

BACKGROUND

The increasing and extensive use of pesticides worldwide has resulted in a significant loss of non-target populations particularly humans by direct or indirect exposures. Also, various methods have been used for the estimation of pesticide residues in fruits and vegetables from recent past which are either tedious, time consuming or expensive. Therefore, the present study was performed to determine the pesticide residues from apple by simple and novel validated gas chromatography.

RESULTS

A novel, accurate, ecofriendly and cost-effective gas chromatography method was developed for simultaneous quantification of eight pesticides, namely chlorpyrifos-methyl (1), chlorpyrifos (2), quinolphos (3), profenofos (4), myclobutnil (5), ethion (6), fenpropathrin (7) and cypermethrin (8). The developed method was validated as per the SANTE guidelines. All calibration curves showed a good linear relationship (r > 0.99) within the test range. Precision was evaluated by intra- and inter-day tests with relative standard deviations (RSDs) < 2.0%, recovery in between 70% and 120% with RSDs < 2.00%.

CONCLUSION

The results demonstrate that the concentration of pesticides 1 to 8 were found below the detectable limit. Method validation parameters like linearity, precision, accuracy, specificity, robustness, detection and quantification limits were found within the acceptable range. The proposed method makes it possible to determine simultaneously pesticides 1-8 in one run which can be extended for residue-based standardization of pesticides from apple and other fruits and vegetables. © 2019 Society of Chemical Industry.

Chromatographic Method for Determination of the Amino Acid Content in Dioscorea bulbifera L. Tubers by RP-HPLC

Background: The present study was carried out for determination of amino acid content in tubers of Dioscorea bulbifera using reverse-phase high-performance liquid chromatography. Methods: The method involved the vapor phase hydrolysis of the sample, automated derivatisation of the amino acids with the aid of AccQ-Fluor reagent kit, separated on a high performance liquid chromatography equipped with photo diode array (HPLC-PDA) at 254 nm having column temperature of 37 ºC. Results: The proportional molar concentration for each amino acid was calculated based on the concentration of standard amino acids and expressed as μg amino acid/mg sample. Methionine, aspartic acid and leucine were major components while as tyrosine was found minor from the plant on dry weight basis. Conclusion: The method is reliable, simple and economical for determining the amino acid content of Dioscorea bulbifera tubers.