Pesticide Residue Fast Screening Using Thermal Desorption Multi-Scheme Chemical Ionization Mass Spectrometry (TD-MION MS) with Selective Chemical Ionization

In this work, the detection characteristics of a large group of common pesticides were investigated using a multi-scheme chemical ionization inlet (MION) with a thermal desorption unit (Karsa Ltd.) connected to an Orbitrap (Velos Pro, Thermo Fisher Scientific) mass spectrometer. Standard pesticide mixtures, fruit extracts, untreated fruit juice, and whole fruit samples were inspected. The pesticide mixtures contained 1 ng of each individual target. Altogether, 115 pesticides were detected, with a set of different reagents (i.e., dibromomethane, acetonylacetone, and water) in different polarity modes. The measurement methodology presented was developed to minimize the common bottlenecks originating from sample pretreatments and nonetheless was able to retrieve 92% of the most common pesticides regularly analyzed with standardized UHPLC-MSMS (ultra-high-performance liquid chromatography with tandem mass spectrometry) procedures. The fraction of detected targets of two standard pesticide mixtures generally quantified by GC-MSMS (gas chromatography with tandem mass spectrometry) methodology was much less, equaling 45 and 34%. The pineapple swabbing experiment led to the detection of fludioxonil and diazinon below their respective maximum residue levels (MRLs), whereas measurements of untreated pineapple juice and other fruit extracts led to retrieval of dimethomorph, dinotefuran, imazalil, azoxystrobin, thiabendazole, fludioxonil, and diazinon, also below their MRL. The potential for mutual detection was investigated by mixing two standard solutions and by spiking an extract of fruit with a pesticide’s solution, and subsequently, individual compounds were simultaneously detected. For a selected subgroup of compounds, the bromide (Br-) chemical ionization characteristics were further inspected using quantum chemical computations to illustrate the structural features leading to their sensitive detection. Importantly, pesticides could be detected in actual extract and fruit samples, which demonstrates the potential of our fast screening method.Peer reviewe

The Semantic Space of Social Networks: Book Review of “Networks 4.0. Complexity Management” / ed. by A.N. Raskhodchikov. Moscow: VCIOM, Social Research Agency “Stolitsa”, 2020. 132 p

The Semantic Space of Social Networks: Book Review of “Networks 4.0. Complexity Management” / ed. by A.N. Raskhodchikov. Moscow: VCIOM, Social Research Agency “Stolitsa”, 2020. 132

The effectiveness of enzyme preparations in broiler chicken diets

With the wrong use of antibiotics for agricultural poultry, the effectiveness of their effect on the body is noticeably reduced, since pathogenic and conditionally pathogenic microorganisms become resistant to them for a certain time, i.e., there is a process of “addiction“. Experience shows that enrichment of feed rations with enzyme preparations and vitamins improves the functioning of the stomach and intestines, increases the natural resistance of the body, as a result of which the mortality of poultry decreases, the absorption of feed is significantly increased and their costs per unit of production are reduced. We studied the effect of the new vitamin-enzyme complex Vitaferm on the organism of broilers against the background of the exclusion of antibacterial drugs from the antiepizootic measures scheme and compared its effect with the enzyme preparation Avizim 110. The studies carried out indicate the positive effect of Vitafarm and Avizim 110 on the poultry organism, which is manifested by an increase in average daily poultry gains, an increase in safety, and a decrease in feed costs per unit of production. These changes can be explained by the normalization of the gastrointestinal tract of broiler chickens and increased immunity. Antibiotics suppress the body’s immune system; upset the balance of the intestinal microflora. For the complete or partial exclusion of antibacterial drugs from the scheme of antiepizootic measures, it is proposed to apply to broiler chickens with feed the vitamin-enzyme complex of Vitaferm at the rate of 15.0 g / kg starting from day old for 10 days

Atmospheric pressure thermal desorption chemical ionization mass spectrometry for ultra-sensitive explosive detection

Illegal explosives are a threat to aviation, transport sector, critical infrastructure and generally to public safety. Their detection requires extremely sensitive instruments with efficient workflows that allow large throughput of items. In this study, we built a trace explosives detection instrument that requires minimal sample treatment and reaches ultra-low picogram level detection limits for many common explosives. The instrument is based on thermal desorption of filters, which allows analysis of liquid and solid phase samples, and subsequent selective atmospheric pressure chemical ionization and detection with a mass spectrometer. We performed experiments to scope the optimal ionization chemistry for the system and selected Br− as the reagent ion, and measured the limit of detection for 14 different explosives that were generally in the picogram range. Finally, we demonstrate the usability of the system by sampling air to a filter from a storage room known to contain explosives, from which we detect four different explosives.</p

Pesticide Residue Fast Screening Using Thermal Desorption Multi-Scheme Chemical Ionization Mass Spectrometry (TD-MION MS) with Selective Chemical Ionization

In this work, the detection characteristics of a large group of common pesticides were investigated using a multi-scheme chemical ionization inlet (MION) with a thermal desorption unit (Karsa Ltd.) connected to an Orbitrap (Velos Pro, Thermo Fisher Scientific) mass spectrometer. Standard pesticide mixtures, fruit extracts, untreated fruit juice, and whole fruit samples were inspected. The pesticide mixtures contained 1 ng of each individual target. Altogether, 115 pesticides were detected, with a set of different reagents (i.e., dibromomethane, acetonylacetone, and water) in different polarity modes. The measurement methodology presented was developed to minimize the common bottlenecks originating from sample pretreatments and nonetheless was able to retrieve 92% of the most common pesticides regularly analyzed with standardized UHPLC–MSMS (ultra-high-performance liquid chromatography with tandem mass spectrometry) procedures. The fraction of detected targets of two standard pesticide mixtures generally quantified by GC–MSMS (gas chromatography with tandem mass spectrometry) methodology was much less, equaling 45 and 34%. The pineapple swabbing experiment led to the detection of fludioxonil and diazinon below their respective maximum residue levels (MRLs), whereas measurements of untreated pineapple juice and other fruit extracts led to retrieval of dimethomorph, dinotefuran, imazalil, azoxystrobin, thiabendazole, fludioxonil, and diazinon, also below their MRL. The potential for mutual detection was investigated by mixing two standard solutions and by spiking an extract of fruit with a pesticide’s solution, and subsequently, individual compounds were simultaneously detected. For a selected subgroup of compounds, the bromide (Br–) chemical ionization characteristics were further inspected using quantum chemical computations to illustrate the structural features leading to their sensitive detection. Importantly, pesticides could be detected in actual extract and fruit samples, which demonstrates the potential of our fast screening method