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

Residues determination, risk assessment, and dissipation behavior of myclobutanil formulation on apple

This study aimed to investigate the dissipation pattern, risk assessment, and waiting period of myclobutanil on apple fruit (Malus domestica Borkh.) under temperate conditions in Kashmir, India. The study involved the application of myclobutanil 10 WP at a single recommended dosage (125 g a.i. ha-1) and double dosage (250 g a.i. ha-1) on Red Velox apple trees, 2 months before harvest. GC equipped with an electron capture detector was used to analyze myclobutanil residues in fruit samples. The study revealed that myclobutanil, at both recommended and double recommended doses, dissipated rapidly and became nondetectable after 55 and 60 days, respectively. The waiting period for myclobutanil application was determined to be 12.41 days for the single dose and 25.58 days for the double dose, respectively. These waiting periods were based on the maximum residue limit of 0.6 ppm as prescribed by the Codex Alimentarius Commission, Food Safety and Standards Authority of India, and European Commission. The study concludes that myclobutanil 10 WP is safe for consumers at both recommended and double recommended doses when applied 2 months before harvest. Risk assessment, considering the average daily apple consumption in India and theoretical maximum residue contributions (TMRCs), indicates negligible health hazards even at double the recommended dosage. The calculated TMRC values at Day 0 were significantly below the maximum permissible intake. For average and maximum myclobutanil residues at single and double doses, the TMRC values were found to be 0.0069 and 0.0070 mg day-1 person-1 and 0.0105 and 0.0106 mg day-1 person-1, respectively. These results indicate that myclobutanil, when used according to recommended dosages and waiting periods, poses minimal health risks to consumers. The study emphasizes the importance of prudent fungicide use to minimize fungicide residues on fruits, thereby ensuring their safety for consumption.

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.

Cumulative health risk assessment of pesticide residues in apple products in the Northwest of Iran using Monte Carlo simulation

Pesticide residues in fruits and vegetables cause serious health issues, especially among children. This research was carried out to monitor and evaluate the risks of organophosphate pesticide residues in Maragheh County apple products from 2020. The Monte Carlo Simulation approach (MCS) was used to evaluate the non-cancerous effects of exposure to pesticide residues in adults and children. Apple samples were taken every two weeks at the Maragheh central market during the summer and fall months. In this study, seventeen pesticide residues in 30 apple samples were estimated using a modified QuECheRS extraction technique coupled with GC/MS. Of the seventeen organophosphate pesticides, thirteen were identified as pesticide residues (76.47%). The highest concentration found in the apple samples was associated with chlorpyrifos pesticide at 1.05 mg/kg. Pesticide residues exceeding the maximum residue limits (MRLs) were found in 100% of apple specimens, and more than 75% of the samples contained ten or more pesticide residues. Approximately 45%-80% of pesticide residues on apple samples were removed after washing and peeling. Chlorpyrifos pesticide had the highest health quotient (HQ) for men, women, and children with values of 0.046, 0.054, and 0.23, respectively. Cumulative risk assessment (CRA) of non-carcinogenic effects indicates that there is no significant health risk in the adult age group from apple consumption (HI < 1). Nevertheless, children are at high non-cancer risk from eating unwashed apples (HI = 1.3). This finding shows that high levels of pesticide residues in apple samples, especially unwashed apples, can be a serious concern for the health of children. To better protect consumer health, continuous and regular monitoring, strict regulations, training, and awareness of farmers, especially control pre-harvest interval (PHI) is recommended.

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.

Establishment of Residual Methods for Matrine in Quinoa Plants and Soil and the Effect on Soil Bacterial Community and Composition

A method was developed for the determination of matrine residues in quinoa (Chenopodium quinoa Willd.) plants and soil by liquid chromatography triple quadrupole tandem mass spectrometry (LC-MS/MS) with QuEChERS clean-up. Matrine from soil, quinoa roots, stems, leaves and seeds was extracted with 25% ammonia, 20 mL acetonitrile/methanol, salted with sodium chloride (NaCl) and purified with anhydrous magnesium sulfate (MgSO₄), N-propyl ethylenediamine (PSA) and graphitized carbon black (GCB). Then a chromatographic separation was performed on a Shim-pack XR-ODS II (75 mm × 2.0 mm, i. d., 2.2 µm) column with a gradient elution of 5 mmol/L ammonium formate-methanol as the mobile phase and monitored in multiple reaction monitoring modes (MRM) in electrospray positive ionization mode. The results showed that in the range of 0.005~1 mg/L, the linear correlation coefficients of matrine in the five matrices were all above 0.999. The LOQs for soil, quinoa roots, stems, leaves and seeds were 0.005, 0.005, 0.01, 0.01 and 0.005 mg/kg, respectively. The mean recoveries ranged from 74.42% to 98.37%, with RSDs of 1.25-6.84% at the three concentration addition levels. The average intra-day and inter-day recoveries were 73.92-92.36% and 78.56-90.18%, respectively, with RSDs below 8.72% and 9.43%. The recoveries and reproducibility of the method were superior. The method was used to determine the actual samples, which indicated that the half-lives of matrine in quinoa seeds, leaves, stems and soil were 1.28-1.32, 1.03-1.21, 0.81-0.92 and 0.93-0.97 d. It has a half-life below 30 d, which is an easily dissipated pesticide. The method is simple, sensitive, accurate, reliable and applicable to a wide range of applications, and it can achieve the rapid multi-residue determination of matrine to a certain extent. Next Generation Sequencing was used to explore the effects of exposure to high and low doses of matrine on soil bacterial communities and the composition of the three soils in the Qinghai Province (Haixi, Haidong and Haibei). The results showed that the number of ASVs increased significantly after treatment with matrine at an effective dose of 0.1 mg/kg than after treatment with matrine at an effective dose of 5.0 mg/kg. Similarly, bacterial abundance was higher after 0.1 mg/kg of matrine treatment than after 5.0 mg/kg of matrine treatment. The inhibitory effect on some bacterial flora was enhanced with an increase in matrine application, while the inhibitory effect on bacterial flora was weakened with time. Applying a certain dose of matrine e changed the relative abundance of the dominant bacterial genera of the soil bacteria.

Highly selective monoclonal antibody-based fluorescence immunochromatographic assay for the detection of fenpropathrin in vegetable and fruit samples

Fenpropathrin (FPT) is a typical pyrethroid pesticide that can cause chronic toxicity to humans. Herein, an anti-FPT monoclonal antibody (mAb) was elicited via a novel hapten synthesized by introducing a carboxyl-containing spacer arm in the cyclopropane moiety of FPT. Characterized by enzyme-linked immunosorbent assay (ELISA), the mAb exhibited high affinity and selectivity to FPT with a half-maximal inhibitory concentration of 31.05 μg/L and negligible cross-reactivities with analogs of pyrethroids. Based on the mAb, a fluorescence immunochromatographic assay (FICA) for FPT detection was firstly developed. The detection limit of the FICA is 0.012 mg/kg which is much lower than the maximum residue limit of FPT for food samples. The average recoveries of FPT from spiked food samples by the FICA were 85.0-105.0%, and the obtained results were in good agreement with those of gas chromatography-tandem mass spectrometry. Overall, this work provided a reliable tool suitable for the detection of FPT residue for large-scale samples in a rapid and cost-effective manner.

Advanced visual sensing techniques for on-site detection of pesticide residue in water environments

Pesticide usage has increased to fulfil agricultural demand. Pesticides such as organophosphorus pesticides (OPPs) are ubiquitous in world food production. Their widespread usage has unavoidable detrimental consequences for humans, wildlife, water, and soil environments. Hence, the development of more convenient and efficient pesticide residue (PR) detection methods is of paramount importance. Visual detecting approaches have acquired a lot of interest among different sensing systems due to inherent advantages in terms of simplicity, speed, sensitivity, and eco-friendliness. Furthermore, various detections have been proven to enable real-life PR surveillance in environment water. Fluorometric (FL), colourimetric (CL), and enzyme-inhibition (EI) techniques have emerged as viable options. These sensing technologies do not need complex operating processes or specialist equipment, and the simple colour change allows for visual monitoring of the sensing result. Visual sensing techniques for on-site detection of PR in water environments are discussed in this paper. This paper further reviews prior research on the integration of CL, FL, and EI-based techniques with nanoparticles (NPs), quantum dots (QDs), and metal-organic frameworks (MOFs). Smartphone detection technologies for PRs are also reviewed. Finally, conventional methods and nanoparticle (NPs) based strategies for the detection of PRs are compared.

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.

Interference-resistant aptasensor with tetrahedral DNA nanostructure for profenofos detection based on the composites of graphene oxide and polyaniline

In this work, an interference-resistant electrochemical aptasensor that could detect profenofos in vegetables was constructed based on complexes of graphene oxide and polyaniline (GO@PANI) and gold nanoparticles-tetrahedral DNA nanostructure (Au-TDN). Compared with a single chain aptamer, the tetrahedral DNA nanostructure is highly stable and allows the aptamer on this structure to stand in a highly ordered position on an electrode surface. Moreover, the AuNPs are biocompatible and can protect the activity of the aptamer, which can improve the assembly success rate of Au-TDN. Besides, the conductivity of PANI had been tremendously enhanced thanks to the existence of GO, which improved the dispersion of PANI. The GO@PANI was prepared by a chemical synthesis method, which had a large surface area and was able to adsorb many Au-TDN. Under optimal working parameters, the constructed aptasensor exhibited good electrochemical sensing performance with a detection limit of 10.50 pg/mL and a linear range of 1.0 × 10²-1.0 × 10⁷ pg/mL. In addition, it was employed in detecting profenofos in vegetables with a good recovery rate of 90.41-116.37 %. More importantly, the aptasensor also has excellent stability and high selectivity. This study provides a promising method to avoid interference in the detection of profenofos by sensors.

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.

A sensitive fluorescent assay for the determination of parathion-methyl using AHNSA probe with MnO2 nanosheets

In this paper, a novel fluorescence assay has been constructed for the determination of parathion-methyl (PM) by using 4-amino-3-hydroxy-1-naphthalenesulfonic acid (AHNSA) as probe. MnO₂ nanosheets (MnO₂ NS) could quench the fluorescence of AHNSA, while Mn²⁺, the reduction product of MnO₂ NS, has no influence on it, resulting in fluorescence recovery. This is because that MnO₂ NS have oxidized characteristic, and they can react with choline (TCh), which is the product of acetylthiocholine (ATCh) catalyzed by acetylcholinesterase (AChE). In the presence of OPs, the activity of AChE was inhibited, accompanied by the restraint of the redox reaction of MnO₂ NS, therefore the fluorescence of AHNSA was quenched. Under the optimized experimental conditions, a linear range of PM was determined to be 0.4-40 ng/mL (R² = 0.997) by the proposed method with the limit of detection for 0.18 ng/mL (S/N = 3). The assay was successfully applied to the determination of PM in lake water, which average recoveries were between 86.5% and 114.4%.

What are the Main Sensor Methods for Quantifying Pesticides in Agricultural Activities? A Review

In recent years, there has been an increase in pesticide use to improve crop production due to the growth of agricultural activities. Consequently, various pesticides have been present in the environment for an extended period of time. This review presents a general description of recent advances in the development of methods for the quantification of pesticides used in agricultural activities. Current advances focus on improving sensitivity and selectivity through the use of nanomaterials in both sensor assemblies and new biosensors. In this study, we summarize the electrochemical, optical, nano-colorimetric, piezoelectric, chemo-luminescent and fluorescent techniques related to the determination of agricultural pesticides. A brief description of each method and its applications, detection limit, purpose—which is to efficiently determine pesticides—cost and precision are considered. The main crops that are assessed in this study are bananas, although other fruits and vegetables contaminated with pesticides are also mentioned. While many studies have assessed biosensors for the determination of pesticides, the research in this area needs to be expanded to allow for a balance between agricultural activities and environmental protection.