Amani M.D.El-Mesallamy

Residues, half-life times, dissipation, and safety evaluation of the acaricide fenpyroximate applied on grapes

A validated high-performance liquid chromatography–diode array detector method for simultaneous determination of the acaricide fenpyroximate on grape was developed. Estimated limit of detection and limit of quantification for fenpyroximate were 0.01 and 0.05 mg kg−1, respectively. The intra- and inter-day precisions performed with relative standard deviation were better than 9.3% and 8%, respectively, while recoveries were in the range of 88.5%–100.4%. Residue levels of fenpyroximate in grape samples collected 10 days after field application were below the established maximum residue level values. The dissipation rates of fenpyroximate were described using first-order kinetics and its half-life, were approximately 3.5 days in grape. This study provides basic information for developing regulations to safeguard the use of fenpyroximate in grapes and prevent any potential health concerns for consumers.

Antioxidant, Antimicrobial Activities and Volatile Constituents of Clove Flower Buds Oil

Abstract In this study, tenth volatile compounds were identified by using gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS). The results showed that the essential oils mainly contained about 75.8 % eugenol and 18.98 % eugenyl acetate. The antioxidant activity was measured by 2, 2’- Diphenyl Picrylhydrazyl (DPPH) radical scavenging method at three different concentrations 25, 50, 100 μl. This volatile oil showed strong antioxidant activity against DPPH as compared with vitamin E. Antimicrobial activities of essential oil were studied against three bacterial strains (E. coli., Staphyllococcus aureus and Salmonella typhi) and four fungal species (Fusarium oxysporum, Aspergillus niger, Penicillium sp. and Trichodermasp) at concentration 0.1 ml and 0.3 ml (10 mg / 1 ml)). The volatile oil had strong inhibitory effect for all bacterial and fungal species at concentration 0.3 ml (10 mg / 1 ml) of the volatile oil.

Health Hazard Assessment of Pyridaben Residues in Egyptian Strawberries

ABSTRACT Dissipation behavior and hazard assessment of the insecticide/acaricide pyridaben applied to strawberries were investigated under the climatic conditions of Egypt. A validated gas chromatographic method (GC-μECD) was used to determine pyridaben residues when applied at the recommended rate and twice this rate. The average recoveries were in the range between 95.8% and 103% with associated relative standard deviation not exceeding 14.5%. The estimated limit of quantification for pyridaben was 0.005 mg/kg. The field results showed that pyridaben dissipated rapidly in strawberries and had a half-life of approximately 2.3 days. The hazard assessment was evaluated by using the hazard quotient (HQ). The results showed that the HQ value was significantly less than HQ = 1. This result implied that the hazard of pyridaben use in strawberries even at double the recommended dosage was negligible to human. This study could provide guidance for the safe and reasonable use of pyridaben in strawberries and to prevent health problems to consumers; however, further hazard assessment studies are needed to ascertain the hazard of pyridaben residues on strawberries to vulnerable groups, including children, pregnant women, and elderly consumers.

Mechanical properties and microstructure of innovative bio-mortar containing different aggregates

Abstract The aim of this work is to study the effect of aggregate type on the physico-mechanical properties and microstructure of bio-mortar (BM). Three different aggregates such as sand, dolomite and basalt were used. BM was prepared by mixing aggregates with bacterial cells (Sporosarcina Pasteurii) and one equimolar (1 M) of urea/CaCl2.2H2O. The results proved that the chemical composition and physical properties of aggregates play an important role in the microbial precipitation rate as well as size, morphology and crystallinity of the precipitated calcite, which strongly reflects on the properties of the prepared BM. The BM containing dolomite gave the highest compressive strength and lowest water absorption.