Search

Catechins, as powerful flavonoids with antioxidant properties, are crucial for the preservation of the human body against free radicals and for promoting overall health. Research has shown that the presence of catechins in urine is linked to a reduced risk of gastric and esophageal cancer. This study introduces an innovative approach using a novel nano‐composite material, composed of magnetic graphene oxide coated with a biocompatible O‐carboxymethyl chitosan/acrylic acid copolymer, for extracting catechins from human urine. The extracted catechins were then analyzed using gas chromatography/mass spectrometry‐selected ion monitoring analysis. Under the optimum conditions, the analytical figures of merit for catechin and epicatechin were linear dynamic range: 0.5–1000 ng/mL, R2 of 0.9991; limit of detection equal to 0.1 ng/mL; relative standard deviation: 4.1 and 3.1 (C = 50 ng/mL, n = 3); and relative recovery was 94%, respectively. The application of this method holds significant promise for advancing clinical and toxicological studies, as well as establishing potential associations between tea consumption and disease prevention. [ABSTRACT FROM AUTHOR]

Fusarium wilt is a fungal disease that has a significant impact on chickpeas worldwide. This study examined the response of 58 chickpea genotypes to Fusarium wilt. The experiment was conducted over two growing seasons at the Sararoud and Maragheh research stations at the Drylands Agricultural Research Institute of Iran. Genotype resistance was screened through wilt incidence records and nonparametric stability statistic evaluation. The identified resistant genotypes were then evaluated in the greenhouse for their response to four isolates of Fusarium oxysporum f. sp. ciceris (races 1/BC, 2, 4, and 6). Out of 58 genotypes, 32 exhibited moderate resistance, while 24 showed strong resistance abilities. Under warmer conditions, disease severity was higher, with scores at the Sararoud location being higher than those at the Maragheh location. Of the total genotypes across all locations and years, 41.4% were resistant, 55.17% were moderately resistant, 1.72% were susceptible, and 1.72% were highly susceptible. The nonparametric stability measures S(1), S(2), and S(3) identified FLIP 05-42C and FLIP 05-43C as stable and resistant genotypes. The study found that Azad/Hashem K3 was stable based on the non-parametric stability measure S(6). Other resistant genotypes were identified using stability parameters NP(1), NP(3), and NP(4), while FLIP 05-104C was identified by NP(2). The genotypes selected by nonparametric stability parameters showed resistance against at least two Fusarium oxysporum f. sp. ciceris races. The screening method and nonparametric stability statistics used in this study were effective in identifying sources of resistance to Fusarium oxysporum f. sp. ciceris. [ABSTRACT FROM AUTHOR]

An electrospun polyethylene terephthalate/graphene oxide nanofibrous mat was fabricated and used as an effective and novel membrane for the solid-phase extraction of tamoxifen in human blood plasma samples before detection by high-performance liquid chromatography. The membrane was characterized by some identification techniques, such as FTIR spectroscopy, X-ray diffraction, and scanning electron microscopy. The effective variables of the extraction procedure including desorption condition (type and volume of the eluent), adsorbent dose, pH of sample solution, salt concentration, and sample loading time were investigated and their optimum values were obtained using one factor at a time methodology. Under the optimized conditions, the results showed wide linear concentration range of 5-2000 ng/mL with a determination coefficient of 0.992. The limits of detection and limits of quantification were 1.3 and 5.0 ng/mL, respectively. The intra-day and inter-day precisions were 3.4 and 4.6%, respectively. The method was successfully applied to determination of tamoxifen in the blood plasma samples and satisfactory relative recoveries (92.6-98.3 %) were achieved. [ABSTRACT FROM AUTHOR]

Highlights: [•] DLLME–GC–NPD was developed for fast determination of caffeine in beverages. [•] GC–NPD a highly specific with sensitivity for nitrogen containing compounds. [•] A very fast and simple extraction, with low LOD, good EF and wide LDR (104). [•] The low volumes of organic solvent (20μL) and sample solution (1mL) are required. [ABSTRACT FROM AUTHOR]

In this study, the optimized ultrasound-assisted emulsification-microextraction followed by inductively coupled plasma-optical emission spectrometry was applied to simultaneous extraction and determination of holmium (Ho3+) and ytterbium (Yb3+) in water samples. 1-(2-Pyridylazo)-2-naphthol was used as chelating agent to form extractable complexes. Volume of extraction solvent, concentration of chelating agent, pH, ultrasonic time, temperature, and concentration of salt were considered as the variables of the method. To evaluate the results, extraction recovery was selected as the response. Significance of the variables was investigated by using a half-fraction factorial design (2f−1) and the optimization was performed by applying a central composite design. The calibration graphs were linear in the range of 4-200 µg L−1 for Ho3+ and 3-500 µg L−1 for Yb3+ with determination coefficients ( R2) of 0.988 and 0.997 for Ho3+ and Yb3+, respectively. Limit of detection was 0.364 µg L−1 for Ho3+ and 0.252 µg L−1 for Yb3+. The relative standard deviations ( C = 200 µg L−1, n = 6) were in the range of 4.2-4.5%. The method was successfully applied to the analysis of real water samples with the recoveries in the range of 80-95%. [ABSTRACT FROM AUTHOR]

In this study, a simple and efficient method of ligandless-ultrasound-assisted emulsification microextraction (LL-USAEME) followed by inductively coupled plasma-optical emission spectrometry (ICP-OES) has been developed for simultaneous extraction, preconcentration and determination of manganese, cadmium, cobalt and nickel in water samples. In the proposed approach, tetrachloroethylene was selected as extraction solvent. The effect of important experimental factors such as volume of extraction solvent, pH, sonication time, salt concentration, and temperature was investigated by using a fractional factorial design (25−1) to identify important factors and their interactions. In the next step, a Box-Behnken design (BBD) was applied for optimisation of significant factors. The obtained optimal conditions were: 30 µL for extraction solvent, 12 for pH, 5 min for sonication time, and 5% w/v for salt concentration. The limits of detections (LODs) for Cd(II), Co(II), Mn(II) and Ni(II) were 0.20, 0.13, 0.21 and 0.28 µg L−1, respectively. Relative standard deviations (RSD, C = 200.0 µg L−1,n = 9) were between 3.4–7.5% and the calibration graphs were linear in the range of 0.25 to 1000.0 µg L−1for Mn, 0.5–1000.0 µg L−1for Co and Ni and 1.0–250.0 µg L−1for Cd. The determination coefficients (R2) of the calibration curves for the analytes were in the range of 0.993 to 0.999. The proposed method was validated by using two certified reference materials, and also the method was applied successfully for the determination of heavy metals in different real water samples. [ABSTRACT FROM AUTHOR]

In this study, optimized ultrasound-assisted emulsification–microextraction (USAEME) combined with inductively coupled plasma-optical emission spectrometry (ICP-OES) was applied to simultaneous determination of trace levels of lanthanum (La) and cerium (Ce) in water and biological samples. 5,6,14,15-dibenzo-1,4-dioxa-8,12-diazacyclopentadecane (a dioxa-diazamacrocycle) was used as chelating agent. Tetrachloroethylene was selected as extraction solvent. The effective parameters of USAEME including pH, salt effect, ultrasonic time, temperature, volume of extraction solvent, and concentration of the chelating agent were studied by a fractional factorial design to identify the significant parameters and their interactions. The results showed that pH and concentration of chelating agent were significant. In the next step, to optimize important parameters, a central composite design was performed. Under the optimal conditions (5.5 for pH and 180 mg L−1 for concentration of chelating agent) the calibration graphs were linear in the range of 0.1–1000 for La and 1–1000 µ g L−1 for Ce. The determination coefficients (R2) were 0.999 and 0.998 for La and Ce, respectively. The limits of detection were 0.012 for La and 0.61 µ g L−1 for Ce. The relative standard deviations (RSD %, n = 7) at 200 µ g L−1 were 3.5% for La and 3.1% for Ce. The method was successfully applied to the analysis of La and Ce in real water samples with the recoveries in the range of 93–99% [ABSTRACT FROM AUTHOR]