A method for the determination of glyphosate (Gly), glufosinate (Glu) and aminomethylphosphonic
acid (AMPA) was developed and validated in tea samples (loose leaf and tea-bag tea types) using
reversed-phase high performance liquid chromatography (RP-HPLC) coupled with tandem
mass-spectrometry. The sample preparation method was consists of: extraction by acidified water
followed by SPE on Oasis HLB, derivatization by FMOC-Cl, concentration and usage of another SPE
stage on Oasis WCX. The limit of quantification (LOQ) of 0.05 mg/kg was reached for Gly and Glu;
0.1 mg/kg for AMPA. Recovery values ranged from 94% to 115% in depending of analyte and
concentration level. The RSD values were ranged from 3 to 15%. The correlation coefficients were
higher than 0.99. The method was applied in 2021-22 for analysis of tea samples, which revealed
about 82% of positives above LOQ level and about 38% of positives with concentrations more than
0.2 mg/kg. Three samples with concentrations of glyphosate between 1-1.07 mg/kg were found. The
glyphosate content in green tea was less in 3 times, in comparison with black tea.
Acute toxicity of chitosan samples was determined by the value of 50% lethal dose (LD50) in experiments on white nonlinear mice aged 2-2.5 months weighing 18-22 g, from which groups of 10 animals were formed. Chitosan preparations were administered once intraperitoneal in a volume of 0.5 cm3 (solution in acetic acid). For control animals, an aqueous solution of acetic acid with a pH of 5.8 was used. The animals were observed after injections of the tested drugs for two weeks. We took into account the appearance and behavior, the state of the coat and visible mucous membranes, the attitude to feed, mobility, volume and frequency of breathing, the timing of the death of animals or their recovery. The radioprotective properties of chitosan against ionizing radiation were investigated. The preventive and therapeutic effect of low-molecular chitosan in intraperitoneal administration at doses of 200 mg / kg live weight in experiments on male mice weighing 20-25 g, subjected to gamma irradiation at doses up to 800 BER (BER - man roentgen equivalent) on the installation "Gamma-panorama" (radiation source Cs137, duration 58.5 min.). It was shown that mice of the experimental group I, which were administered chitosan three days before irradiation, remained alive during the entire observation period (30 days.). Animals II, III and IV of the experimental group was injected with 3, 9 and 22 days after irradiation, the survival rate to the end of the experiment they accounted for 86, 43 and 29%, respectively, with 100% mortality in the control (irradiated animals without the use of chitosan) and intact animals in the control II (non-irradiated animals).
Pesticide residues were analyzed in dead honeybees by gas chromatography-tandem mass spectrometry
(GC-MS/MS). Sample preparation using QuEChERS was followed by purification on a mixture of
PSA and C18 sorbents. The extraction efficiency of > 80% was obtained for all analytes and pesticides
were quantified in the range of 5-1000 ng/g. This method was used for investigating incidents of
honeybees poisoning by pesticides. Fipronil was detected in all of the investigated samples originating
from different regions of Russia. Additionally, τ-fluvalinate was detected in three samples.
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