Dissipation, risk assessment, half‐life period and method validation of carbendazim and triazophos in green pea by high‐performance liquid chromatography

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.

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.

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.

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.

Development, method validation and simultaneous quantification of eleven bioactive natural products from high altitude medicinal plant by high performance liquid chromatography

Herein, a novel, rapid, reliable, simple method validation and simultaneous quantification of eleven bioactive compounds mostly xanthones have been described. ICH guidelines were used for the analytical method validation. Good linearity, repeatability, intra-day and inter-day precision, accuracy and reliability is well illuminated in the method validation procedure. The calibration curves showed a good linear relationship (r>0.999) within test range. Precision was evaluated by intra- and inter-day tests with RSDs <2.79%, accuracy validation recovery 74.16-91.84%. On quantification study, validated method described the high content of bioactive xanthone derivative including 1-hydroxy-3, 5-dimethoxyxanthone (7), 2-(allyloxy)-8-hydroxy-1, 6-dimethoxyxanthone (6) 1, 7, 8-trihydroxy-3-methoxyxanthone (9) and Coxanthone E (5) in the C. ovata which is advantageous due to numerous pharmacological and biological effects associated with these compounds mostly anti-cancers, antioxidant, anti-inflammatory, anti-mutagenic and anti-obesity activity. The bulk abundance of these compounds can also be used for the further modification to produce better lead molecules for drug discovery with low toxicity and high potency. The proposed method makes it possible to determine simultaneously all bioactive compounds in one run and can be extended for marker based standardization of herbal formulations in medicinal and pharmaceutical industries.

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.