Triple Quadrupole Mass Detector Research Articles

A Validated Method for the Simultaneous Determination of Oxytocin and Cortisol in Human Saliva

Oxytocin and cortisol (OXY and CORT) are hormones related to stress, cognitive, and social behaviors. Their detection is relevant to epidemiological studies aimed at investigating the effects of stressor factors on human life. The aim of this study was to develop and validate an assay for the measurement of OXY and CORT in saliva samples using liquid chromatography/tandem mass spectrometry (LC-MS/MS) in the presence of deuterated analogs. A 500 mL aliquot of oral fluid, obtained by the centrifugation of a chewed swab, was purified by solid-phase extraction. Analytes were then separated using C18 reversed-phase chromatography, subjected to positive electrospray ionization, and then quantified using a triple-quadrupole mass detector in multiple-reaction monitoring mode. The limits of quantification and the linear dynamic ranges were 2.0 × 10−3 and 0.5 nmol/L, and up to 1.0 × 10−1 and 20 nmol/L for OXY and CORT, respectively. Inter- and intra-run precision, expressed as relative standard deviation, was <7%, and accuracy was within 93–104% of the theoretical concentrations. The evaluation of matrix effects showed that the use of internal standards controlled sources of bias. The high sensitivity of the method allowed the quantification of OXY and CORT in the salivary samples of both adults and children: levels of CORT ranged from 0.6 to 18.5 nmol/L, while OXY levels were two orders of magnitude lower (from 1.7 × 10−3 to 1.1 × 10−2 nmol/L). To our knowledge, this is the first method that can analyze, in the same chromatographic run, both hormones in saliva samples.

Trace level quantification of N-nitrosorasagiline in rasagiline tablets by LC-TQ-MS/MS

Parkinson's disease is a chronic, progressive neurological disease that currently affects about more than 10 million population worldwide. Rasagiline is a selective, irreversible monoamine oxidase type B inhibitor used as monotherapy in early Parkinson's disease. Rasagiline tablets have been recalled from market due to the presence of unacceptable levels of nitrosamine impurity. European Medical Agency has set up very stringent limit 100ng/day of N-nitrosorasagiline (NSRG) in drug product based on its mutagenicity. The analytical methods need to be sufficiently sensitive in order to adequately detect and quantify trace levels of NSRG. A highly sensitive LC-MS/MS method for determination of NSRG in rasagiline tablet formulation was developed by effectively separating on zorbax eclipse XDB C18 column using 0.1% formic acid in mixture of water and acetonitrile (35:65 v/v) in an isocratic mode at 0.5mL/min flow rate. The measurement of NSRG was performed using triple quadrupole mass detection accompanied by electrospray ionization in the multiple reaction monitoring mode. The validation of the method was comprehensive, demonstrating strong linearity across the concentration spectrum of 2 to 200ng/mL for NSRG. The obtained correlation coefficient exceeded 0.998, signifying a robust relationship. Recoveries spanning from 80.0% to 120.0% for NSRG were deemed satisfactory. The developed method was able to detect and quantitate NSRG at a concentration level of 1 to 2ng/mL respectively (1 to 2ppm with respect to 1mg/mL of rasagiline tablet sample concentration). The developed and validated method can be employed for routine quality control testing of rasagiline tablets.

Synthesis and Trace-Level Quantification of Mutagenic and Cohort-of-Concern Ciprofloxacin Nitroso Drug Substance-Related Impurities (NDSRIs) and Other Nitroso Impurities Using UPLC-ESI-MS/MS-Method Optimization Using I-Optimal Mixture Design.

Globally, the pharmaceutical industry has been facing challenges from nitroso drug substance-related impurities (NDSRIs). In the current study, we synthesized and developed a rapid new UPLC-MS/MS method for the trace-level quantification of ciprofloxacin NDSRIs and a couple of N-nitroso impurities simultaneously. (Q)-SAR methodology was employed to assess and categorize the genotoxicity of all ciprofloxacin N-nitroso impurities. The projected results were positive, and the cohort of concern (CoC) for all three N-nitroso impurities indicates potential genotoxicity. AQbD-driven I-optimal mixture design was used to optimize the mixture of solvents in the method. The chromatographic resolution was accomplished using an Agilent Poroshell 120 Aq-C18 column (150 mm × 4.6 mm, 2.7 μm) in isocratic elution mode with 0.1% formic acid in a mixture of water, acetonitrile, and methanol in the ratio of 475:500:25 v/v/v at a flow rate of 0.5 mL/min. Quantification was carried out using triple quadrupole mass detection with electrospray ionization (ESI) in a multiple reaction monitoring technique. The finalized method was validated successfully, affording ICH guidelines. All N-nitroso impurities revealed excellent linearity over the concentration range of 0.00125-0.0250 ppm. The Pearson correlation coefficient of each N-nitroso impurity was >0.999. The method accuracy recoveries ranged from 93.98 to 108.08% for the aforementioned N-nitrosamine impurities. Furthermore, the method was effectively applied to quantify N-nitrosamine impurities simultaneously in commercially available formulated samples, with its efficiency recurring at trace levels. Thus, the current method is capable of determining the trace levels of three N-nitroso ciprofloxacin impurities simultaneously from the marketed tablet dosage forms for commercial release and stability testing.

Liquid Chromatography Tandem Mass Spectrometric Method Development and Validation for the Quantification of Orlistat in Biological Matrices

A specific, linear and precise liquid chromatographic-tandem mass spectrometric method was established and validated for the quantitation of orlistat in sample plasma. Zorbax C18 (4.6 mm i.d.× 50.0 mm; 5.0 μm) stationary phase was utilized to achieve chromatography elution, through a flowing rate of 0.90 mL/min. Isocratic elution was done using methanol, acetonitrile and 0.10% v/v HCOOH in a fraction of 80:10: 10 v/v/v as the mobile phasic system. For drug and internal standard separation, the precipitation extraction technique used acetonitrile as solvent. A triple quadrupole mass detector was employed for the quantification of ions. Electrospray ionization in a positive ionizing method, which was executed in multiple reaction monitorings (MRM) with parent/product ion transitions of m/z 496.4→337.31 for orlistat and 506.23→57.07 for amprenavir internal standard. The calibration graph was executed between the concentrations of 4.75–190.0 ng/mL and the resulting equation was y = 0.0058x + 0.0022 with r2 value of more than 0.99. Orlistat recovery values were found to be more than 93.65%, and its accuracy, measured in relative error, was in the range of -4.48 to 3.49%. Accuracy findings, sensitivity and recovery values of orlistat in the sample plasma for the established technique evidences its importance in pharmacokinetic and bioequivalence study.

Stability of pesticide residues in citrus fruits during storage

Introduction. Storage of selected samples before transportation to the laboratory and immediately before analysis is an important component in the process of product quality control and evaluation.
 Purpose of the work was to evaluate the degradation of pesticide active substances in real samples of citrus fruit left for long periods of storage in deep freezing conditions.
 Materials and methods. High-performance liquid chromatography with triple quadrupole mass detector (HPLC-MS/MS) was used to identify and quantify pesticide active substances. According to the method of analysis MUK 4.1.3657–20, cryogenic grinding of samples was carried out in a cutter using dry ice. Sample preparation was carried out using the QuEChERS technology. To extract analytes from a homogenized sample acetonitrile was used in the presence of salts containing citrate buffer, followed by purification of the extract by SPE.
 Results. In the studied samples of citrus, the analytes showed stability. Thirty months after storage of samples in deep freezing conditions (temperature not higher than –20 °C), the identified levels of active ingredients of the pesticides imazalil, pyrimethanil and prochloraz did not change by more than 20% compared to the previously detected concentrations. Insignificant amounts of imidacloprid, thiabendazole and pyriproxyfen, as well as traces of azoxystrobin and trifloxystrobin, detected in the study of samples, were also found in samples after long-term storage. 
 Limitation. The study is limited to the study of the stability of individual active substances found in real samples of citrus fruits intended for sale to the consumer.
 Conclusion. Proper storage of samples should ensure the preservation of the levels of active substances in the samples and exclude their change due to various processes (volatilization, enzymatic and hydrolytic decomposition, etc.), which requires the performance of preliminary experimental studies to assess their stability. The work showed the stability of residual quantities of imazalil, pyrimethanil, prochloraz, imidacloprid, thiabendazole, and pyriproxyfen in citrus fruit matrices under storage conditions in a freezer at not more than –20 °C for 30 months.

Method for quantitative analysis of the marker substrate ABCB1-protein fexofenadine in Caco-2 cell lysate

One way to analyze the activity of the ABCB1 protein is to assess the accumulation of its substrate fexofenadine (F.) inside the test cells. The goal is to develop and validate a method for the quantitative analysis of F. in Caco-2 cell lysate using HPLC-MS/MS. Materials and methods. Caco-2 cell lysate was used as a matrix. The analysis was performed on an "Ultimate 3000" chromatograph with a TSQ Fortis triple quadrupole mass detector, a UCT Selectra C18 4.6 mm*100 mm 5 µm column in a gradient elution mode. The mobile phase rate was 0.3 ml/min, the sample volume was 20 µl, the ionization mode was positive, and the internal standard was amantadine (ng/ml). Sample preparation — precipitation of cell lysate protein with acetonitrile. The method was validated for the following parameters: selectivity, linearity, lower limit of quantitation (LLOQ), correctness, precision, sample transfer and sample stability. Results. Chromatograms of the blank lysate of Caco-2 cells showed no peaks with retention times characteristic of F. (5.70 min) and amantadine (3.58 min). NPKO F. was 0.5 ng/ml. F.'s transfer did not exceed 20% of NPKO, and amantadine — 5%. Based on the results of the analysis of three series of calibration standards (0.5; 1; 1.5; 5; 10; 25; 40; 50 ng/ml), linear regression equations were obtained, the correlation coefficients exceeded 0.99. Accuracy and precision were assessed within and between cycles by analyzing F. solutions in the matrix (0.5; 1.5; 25 and 40 ng/ml) within three cycles. The parameters did not exceed 20% for LLPO and 15% for other points. The stability of F. solutions (1.5 and 40 ng/ml) in the lysate was analyzed during storage at room temperature, after 3-fold freezing-thawing, storage at -80 °C for 60 days, after sample preparation and being in the autosampler for 24 hours. The accuracy was within 15% of the nominal values. Conclusions. A method for the quantitative determination of F. in Caco-2 cell lysate using HPLC-MS/MS has been developed and validated.

Eco-friendly chromatographic platforms for simultaneous determination and impurity profiling of an antihypertensive ternary pharmaceutical mixture

Development of new analytical methods that are capable of determining pharmaceutically active substances in the presence of their related impurities is vital in pharmaceutical industry. Herein, simple, reliable and ecofriendly chromatographic methods were established, optimized and validated for the concurrent estimation of amiloride hydrochloride (AML), hydrochlorothiazide (HCT) and timolol maleate (TIM) along with hydrochlorothiazide potential impurities, salamide (DSA) and chlorothiazide (CT). The first established method was based on high performance liquid chromatography (HPLC-DAD). Separation was achieved using XBridge C18 analytical column and a gradient elution system comprises solvent A [20.0 mM phosphate buffer (pH = 3)] and solvent B [acetonitrile]. UV detection was accomplished at 220.0 nm for AML, HCT and HCT related impurities and at 295.0 nm for TIM. The second method was a LC-MS/MS method for the profiling and quantification of HCT impurities (DSA and CT). Separation was executed on Agilent Poroshell 120 EC-C18 column using mobile phase consisted of methanol and 0.1% formic acid in a ratio of 97:3 (v/v) pumped at flow rate of 0.7 mL/min with a run time of 3.0 min. Impurities were quantified via the utilization of multiple reaction monitoring mode (MRM) and triple quadrupole mass detection with electrospray ionization. The method demonstrated excellent sensitivity and linearity with limit of detection (LOD) of 1.0 ng/mL and 0.1 ng/mL for DSA and CT, respectively. Validation of the suggested methods was achieved in compliance with the ICH guidelines and were successively utilized for the determination of the aformentioned compounds in Moducren® tablets. Additionally, the advantage of the developed HPLC-DAD method was extrapolated for in-vitro drug release monitoring. Greenness of the proposed methods was assessed using different well established assessment tools.

A highly sensitive LC-MS/MS method for the determination and quantification of a recently identified N-nitrosamine impurity in the sitagliptin phosphate monohydrate active pharmaceutical ingredient.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used for the quantification of 7-nitroso-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (NTTP) in the sitagliptin phosphate monohydrate active pharmaceutical ingredient. Chromatographic separation was achieved using an Agilent-ZORBAX SB-C18 column, with 0.01 mol L-1 ammonium formate in water as mobile phase A and acetonitrile as mobile phase B in gradient elution mode at a 0.4 mL min-1 flow rate. Quantification of impurities was carried out using triple quadrupole mass detection with electrospray ionization in the multiple reaction monitoring mode. The method was fully validated with good linearity over the concentration range of 0.098-0.925 ppm of the sitagliptin phosphate monohydrate test concentration for NTTP. The correlation coefficient obtained in each case was >0.998. The recoveries were found to be satisfactory over the range between 80.0 and 120.0% for NTTP. The developed method was able to quantitate NTTP at a concentration level of 0.98 ng mL-1 (0.098 ppm with respect to 10 mg mL-1 sitagliptin phosphate monohydrate).

Assessment of pesticide residues in vegetables commonly consumed in Chile and Mexico: Potential impacts for public health

Pesticides are contaminants that pose serious risks to human health and the environment worldwide; however, little information is available on the occurrence of pesticide residues in vegetables in either Chile or Mexico. This study evaluated the presence of 22 pesticide residues in vegetables sold at supermarkets and farmers markets in Chile and Mexico and estimated the dietary risk. A total of 101 samples collected from 2018 to 2019 were analyzed by the QuEChERS multiresidue method using gas chromatography with a triple-quadrupole mass detector (GC–MS/MS). Eleven pesticide residues (i.e., carbaryl, carbofuran, chlorothalonil, chlorpyrifos, cypermethrin, dimethoate, endosulfan alpha, endosulfan sulfate, lambda-cyhalothrin, methamidophos and monocrotophos) were quantified in chard, lettuce, green chili, tomato, and spinach. The total number and concentrations of these pesticides were greater in Mexico (10) than in Chile (3). Lambda-cyhalothrin was the most common residue in all Chilean and Mexican vegetables. Traces of carbofuran were detected in chard from Chile but not in chard from Mexico. High levels of dimethoate, chlorpyrifos, and methamidophos residues were found in Mexican spinach. Mean pesticide concentrations in Chile did not exceed the maximum residue limits. In Mexico, six pesticides exceeded the maximum residue limits of the European Union in nine conventional and five organically grown crops. However, the sum of the estimated daily intake (EDI) did not exceed the acceptable daily intake (ADI). Continuous monitoring programs and stricter regulations for pesticide residues in vegetables are needed to promote food safety and improve public health in both countries.

Biological monitoring — as a method of hygienic assessment of the effects of pesticides on workers

Introduction. When conducting registration tests of the active substances of pesticides, it is essential to assess the risk for workers using these pesticide preparations in field experiments, where there is a direct human interaction with a potentially hazardous substance. The use of personal protective equipment and strict adherence to the regulations for the use of pesticide preparations cannot guarantee complete protection against contact with aggressive components. Biomonitoring occupies a special place in studies on the assessment of exposure of workers with pesticides, which makes it possible to assess the actual, rather than potential, absorption of a biologically active substance. Purpose of the work. Study of biomaterial (urine) of employees participating in field experiments when working with drugs based on active substances of the neonicotinoid group to determine their trace amounts by high performance liquid chromatography with a mass detector and risk assessment for those working with these pesticides. Materials and methods. Preparation of urine samples and their subsequent analysis for the content of residual amounts of acetamiprid, imidacloprid, thiamethoxam and its metabolite clothianidin were performed in accordance with the certified method “Measurement of the concentration of active substances of pesticides of the neonicotinoid class in urine”. The measurements were carried out using a method based on a tandem high performance liquid chromatography with a triple quadrupole mass detector, which makes it possible to estimate the minimum levels of active substances by two transitions of the parent ions (for quantitative calculation and confirmation by the ionic ratio). Electrostatic sputtering was used as a source of ionization; measurements were carried out in the multiple reaction monitoring mode. Results. The detected levels of imidacloprid in the urine of the researchers correspond to the data on the exposure assessment obtained from the results of measuring the concentration of this active substance in the air of the working area, as well as in washes from the skin of workers in agriculture. The maximum content of imidacloprid was revealed during the sowing of the etched seed material. Conclusion. Based on the data obtained, it was concluded that biomonitoring is the preferred method in a production environment due to its simplicity and sufficient information content.

Eco-Friendly UPLC-MS/MS Quantitation of Delafloxacin in Plasma and Its Application in a Pharmacokinetic Study in Rats

A novel UPLC-MS/MS assay was developed for rapid quantification of delafloxacin (a novel fluoroquinolone antibiotic in plasma samples by one step sample cleanup procedure. Delafloxacin (DFX) and internal standard (losartan) were separated on a UPLC BEH C18 column (50 × 2.1 mm; 1.7 μm) by using gradient programing of a mobile phase containing 0.1% formic acid in acetonitrile and 0.1% formic acid in water. The quantification was performed by a using triple-quadrupole mass detector at an electrospray ionization interface in positive mode. The precursor to the product ion transition of 441.1 → 379.1 for the qualifier and 441.1 → 423.1 for the quantifier was used for DFX monitoring, whereas 423.1 → 207.1 was used for the internal standard. The validation was performed as per guidelines of bioanalytical method validation, and the evaluated parameters were within the acceptable range. The greenness assessment of the method was evaluated by using AGREE software covering all 12 principles of green analytical chemistry. The final score obtained was 0.78, suggesting excellent greenness of the method. Moreover, Deming regression analysis showed an excellent linear relationship between this method and our previously reported method, and it is suitable for high-throughput analysis for routine application. The proposed method was effectively applied in a pharmacokinetic study of novel formulation (self-nanoemulsifying drug delivery systems) of DFX in rats.

On the issue of analytical control of quinone derivatives in habitats

Introduction. In the direction of normative and methodological assurance of the safety of environmental objects and imported food products, analytical approaches to the determination of a fungicide of the quinone class - dithianone in the air and citrus fruits were optimized. Materials and methods. Measurements were performed by tandem liquid mass spectrometry with a triple quadrupole mass detector (HPLC-MS/MS) in multiple reaction monitoring (MRM) mode using electrostatic spray as the ionization source. The substance from the air was concentrated on Tenax TA sorption tubes based on a porous polymer sorbent, followed by extraction of dithianone from the tubes with acetone. The preparation of samples of citrus fruits was carried out by extraction of acidified acetonitrile (selected optimal pH 2) in the presence of salts of magnesium sulfate, sodium chloride and sodium citrate two- and three-substituted, followed by centrifugation and filtration of the extract through disposable syringe membrane filters (QuEChERS technology). Results. The developed techniques were tested on real samples using the pesticide in agricultural practice. The revealed levels of dithianon do not exceed the lower limit of quantitative determination: 0.000071 mg/m3 in ambient air (with an RISL value of 0.0001 mg/m3) and 0.01 mg/kg in citrus fruits (with an established MRL value of 3 mg/kg). Conclusion. The developed methods are approved as official documents and supplement the base of analytical methods in terms of control of atmospheric air and imported food products.

Residual amounts of pesticides in citrus fruits: analytical control

Introduction. Thanks to possessing beneficial properties and vitamin content, citrus fruits occupy a prominent place in the ubiquitous nutrition of all ages due to various crops. On the other hand, due to climatic conditions, they cannot be cultivated in our country and are classified as imported products, which justifies the importance of controlling their safety. Purpose of the work. The creation of a multicomponent method for determining the residual amounts of pesticides and their metabolites in citrus fruits. Materials and methods. HPLC with triple quadrupole mass detector in multiple reaction monitoring (MRM) mode and capillary gas-liquid chromatography with mass selective detector (GC-MC) in selected ion monitoring mode (SIM) together were used to perform the identification and quantitative determination of the active substances of pesticides of various classes (amino pyrimidines, imidazoles, carbamates, strobilurins, triazoles, organophosphorus compounds, etc.) As a sample preparation method, there was used the QuEChERS technology, based on the extraction of pesticides with an organic solvent from a homogenized sample in the presence of salts containing citrate buffer and the purification of the extracts by dispersive solid-phase extraction. Results. To control the safety of citrus fruits (lemons, grapefruits, oranges, tangerines) imported from Egypt, Turkey and Abkhazia, purchased on the food market, a multi-method was used for determining the residual amounts of a wide range of pesticide compounds (50 names of active ingredients of pesticides and their toxic metabolites) in citrus fruits. The identified levels of active pesticide ingredients did not exceed the established MRLs. Conclusion. The modern development of the analytical chemistry of pesticides, the use of a tandem of gas and liquid chromatography with mass spectrometric detection made it possible to implement a group method for the quantitative determination of the active substances of pesticides and their toxic metabolites in citrus fruits. Modern development makes it possible to detect the contamination of their residual amounts in the processed products.

A SELECTIVE AND SENSITIVE LC-MS/MS METHOD FOR QUANTIFICATION OF FOUR POTENTIAL GENOTOXIC IMPURITIES IN ATAZANAVIR SULFATE DRUG SUBSTANCE IN TRACE LEVEL

Objective: The main objective of current research work is to develop and validate a rapid, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the trace analysis of four potential genotoxic impurities in Atazanavir Sulfate drug substance.
 Methods: LC-MS/MS analysis of four potential genotoxic impurities was done on Acquity UPLC CSH C18 (100 mm × 2.1 mm, 1.7 μm) column. In this method, mobile phase A (10 mM ammonium acetate) mobile phase B (methanol: acetonitrile (90:10, v/v) with gradient run with the flow rate of 0.2 ml/min. The method was developed with the short run time of 13 min. Triple quadrupole mass detector coupled with positive electrospray ionization was used for the quantification of genotoxic impurities in multiple reaction monitoring (MRM) mode.
 Results: The method was linear in the range of 0.3 ppm to 4.5 ppm for BOC Hydrazine Acid impurity, BOC Epoxide and Keto impurity with a correlation coefficient not less than 0.9994. The accuracy of the method was in the range of 99.26% to 105.71% for all four potential genotoxic impurities (PGIs). No impurities were identified in the Atazanavir Sulfate active pharmaceutical ingredient sample.
 Conclusion: The proposed method is specific, linear, precise, accurate, robust and stable for the quantification of the four genotoxic impurities at very low levels.

A Selective and Sensitive Method Development and Validation of 1,1-Dimethyl-3-Hydroxy-Pyrrolidinium Bromide Impurity in Glycopyrrolate Oral Solution by Liquid Chromatography-Tandem Mass Spectroscopy.

A selective and sensitive liquid chromatography-tandem mass spectrometer (LC-MS/MS) method has been developed for the quantification of 1,1-dimethyl-3-hydroxy-pyrrolidinium bromide impurity in glycopyrrolate oral solution. The LC-MS/MS analysis was done on X Bridge HILIC (100×4.6mm, 5μm) analytical column, and the mobile phase used was10mM ammonium formate with 0.2% formic acid as mobile phase-A and acetonitrile as mobile phase-B with a gradient programme of 5.0min. The flow rate used was 1.2mL/min. Triple quadrupole mass detector coupled to positive electrospray ionization operated in multiple reactions monitoring mode was used for the quantification at m/z 116.10±0.5. Retention time of impurity was found ~3.2min. The method was validated in terms of specificity, linearity, accuracy, precision, range, limit of detection, limit of quantitation (LOQ) and robustness. Relative standard deviation (RSD) for system suitability was found 1.3%. Calibration plot was linear over the range of 0.050-2.000μg/mL. Limit of detection and limit of quantification were found 0.017 and 0.051μg/mL, respectively. The intra- and inter-day precision RSD was 2.3% and the obtained recovery at LOQ to 200% was in between 86.7 and 107.4%. The low RSD values and high recoveries of the method confirm the suitability of the method.

Synanthropic Plants as an Underestimated Source of Bioactive Phytochemicals: A Case of Galeopsis bifida (Lamiaceae)

Hemp nettle (Galeopsis bifida Boenn.) is a synanthropic species of the Lamiaceae family that is widely distributed across Europe, Asia, and Siberia. Galeopsis bifida is deeply embedded in the ethnomedical tradition of Asian healers; however, this plant is still poorly characterized, both chemically and pharmacologically. To study Siberian populations of G. bifida, we used high-performance liquid chromatography with photodiode array and electrospray triple quadrupole mass detection for metabolic profiling. Ninety compounds were identified, including iridoid glycosides, phenylethanoid glycosides, hydroxycinnamates, and flavone glycosides, most of which were identified in G. bifida for the first time, while some phenolics were found to have potential chemotaxonomic significance in the Lamiaceae family and Galeopsis genus. An unequal quantitative distribution of the selected metabolites was observed within separate organs of the G. bifida plant, characterized by high accumulation of most compounds within the aerial part of the plant (leaves, flowers). Analysis of the content of specific chosen compounds within the leaves of different populations of G. bifida from Eastern Siberia revealed the existence of two chemical types based on metabolic specifics: the southern type accumulates flavone glucuronides, while the northern type tends to accumulate high levels of phenylpropanoids and acylated flavone glucosides. The first study of the bioactivity of G. bifida extract demonstrated that the herb has low toxicity in acute experiments and expresses antioxidant potential against free radicals in the form of DPPH˙, ABTS˙+, and superoxide radical, as well as high ferric reducing antioxidant power, oxygen radical absorbance capacity, and protective action in the carotene bleaching assay. In general, our results suggest the herb of G. bifida as a new, prospective synanthropic plant for medical application.

Oxidative degradation and mineralization of bentazone from water

Bentazone degradation efficiency and mineralization in water solutions using chlorine dioxide treatment were evaluated. Double distilled water and a river water sample spiked with bentazone were studied and compared after chlorine dioxide treatment. Degradation efficiency was determined using high-performance liquid chromatography (HPLC). Daphnia magna toxicity testing and total organic carbon (TOC) analysis were used to ascertain the toxicity of the degraded solutions and mineralization degree. Bentazone degradation products were identified using gas chromatography with a triple quadrupole mass detector (GC-MS-MS). A simple mechanistic scheme for oxidative degradation of bentazone was proposed based on the degradation products that were identified. Decrease in D. magna mortality, high degradation efficiency and partial bentazone mineralization were achieved by waters containing bentazone degradation products, which indicate the formation of less toxic compounds than the parent bentazone and effective removal of bentazone from the waters. Bentazone degraded into four main degradation products. Humic acid from Sava River water influenced bentazone degradation, resulting in a lower degradation efficiency in this matrix (about 10% lower than in distilled water). Chlorine dioxide treatment of water to degrade bentazone is efficient and offers a novel approach in the development of new technology for removal of this herbicide from contaminated water.

Degradation Products, Mineralization, and Toxicity Assessment of Pesticides Malathion and Fenitrothion

The aim of this study was to investigate, analyze, and compare applied techniques suitable for achieving efficient removal of organophosphorus pesticides (OPPs) (malathion and fenitrothion) from aqueous solutions and analyze the degradation products and processes. Pesticide degradation efficiency (%) was monitored by high-performance liquid chromatography (HPLC) equipped with a photodiode array detector (DAD), while mineralization degree was determined by total organic carbon analysis (TOC). Daphnia magna was used for screening the environmental safety aspects of the degradation methods, i.e., for assessing the toxicity of solutions obtained after degradation. Additionally, a surface river water was utilized to examine the likely influence of organic matter on the pesticides’ degradation. Pesticide degradation products were identified using gas chromatography with a triple quadrupole mass detector (GC-MS/MS) as well as ultrahigh-performance liquid chromatography coupled with a linear ion trap, Orbitrap mass spectrometer (UHPLC-LTQ Orbitrap MS), and a simple pesticide degradation mechanism is proposed. Removal of pesticides from water using chlorine dioxide was successful, resulting in high degradation efficiency (98% for malathion and 81% for fenitrothion). Partial mineralization was achieved, and Daphnia magna mortality decreased in the waters containing degradation products (compared with the parent pesticides), indicating that the solutions formed were less toxic than the parent pesticides. Lower degradation rates (80% for malathion and 72% for fenitrothion) in Sava River water were measured, indicating the influence of the organic matter contained in this naturally occurring surface water. The results prove that chlorine dioxide could be used as an agent for successful removal of these OPPs from water.

LC-MS Profile, Gastrointestinal and Gut Microbiota Stability and Antioxidant Activity of Rhodiola rosea Herb Metabolites: A Comparative Study with Subterranean Organs.

Golden root (Rhodiola rosea L., Crassulaceae) is a famous medical plant with a one-sided history of scientific interest in the roots and rhizomes as sources of bioactive compounds, unlike the herb, which has not been studied extensively. To address this deficiency, we used high-performance liquid chromatography with diode array and electrospray triple quadrupole mass detection for comparative qualitative and quantitative analysis of the metabolic profiles of Rhodiola rosea organs before and after gastrointestinal digestion in simulated conditions together with various biochemical assays to determine antioxidant properties of the extracts and selected compounds. R. rosea organs showed 146 compounds, including galloyl O-glucosides, catechins, procyanidins, simple phenolics, phenethyl alcohol derivatives, (hydroxy)cinnamates, hydroxynitrile glucosides, monoterpene O-glucosides, and flavonol O-glycosides, most of them for the first time in the species. The organ-specific distribution of compounds found for catechins, procyanidins, and cinnamyl alcohols and glucosides was typical for underground organs and flavonoids and galloylated glucoses concentrated in the herb. Extracts from rhizomes, leaves and flowers showed high phenolic content and were effective scavengers of free radicals (2,2-diphenyl-1-picrylhydrazyl (DPPH•), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+), O2•−, •OH) and protected β-carotene in a bleaching assay. Digestion in the gastric and intestine phase influenced the composition of R. rosea extracts negatively, affecting the content of catechins, procyanidins, and galloyl glucoses, and therefore, the antioxidativity level. After gut microbiota treatment, the antioxidant capacity of rhizome extract was lower than leaves and flowers due to the aglycone composition found in the colonic phase of digestion. Our study demonstrated that the herb of R. rosea is a rich source of metabolites with high antioxidant properties and could be a valuable plant for new bioactive products.

Examination of degradation and ecotoxicology of pethoxamid and metazachlor after chlorine dioxide treatment.

Chlorine dioxide has been reported as very efficiently removing pesticides and other organic compounds from water matrixes. Due to pesticide toxicity and potential toxicity of their degradation products, it is important to monitor these compounds as environmental pollutants in ground and surface waters. Evaluating the effects of chlorine dioxide treatment is necessary, and toxicity studies are used to ascertain the severity of effects of intermediates due to incomplete degradation of the parent compounds. In this paper, for the first time, chlorine dioxide is applied and evaluated for the removal of chloroacetamide herbicides (pethoxamid and metazachlor) from waters (deionized water and Sava River water). The degradation degree of herbicides was measured by high-performance liquid chromatography, the main degradation products were identified using gas chromatography with a triple quadrupole mass detector, and the degree of mineralization was monitored by total organic carbon analysis. Four and two degradation products were identified after pethoxamid and metazachlor degradation, respectively. Total organic carbon analysis showed mineralization occurred, but it was incomplete. The mineralization and the characteristics of the degradation products obtained were tested using Daphnia magna and showed lower toxicity than the parent herbicides. The advantage of the applied treatment was a very high degradation percentage for pethoxamid removal from deionized water and Sava River water (100% and 97%, respectively), with higher mineralization efficiency (65%) than metazachlor. Slightly lower degradation efficiency in the Sava River water was due to chlorine dioxide oxidizing the herbicides and dissolved organic matter simultaneously.