Large Volume Injection Research Articles

Capillary ultrahigh-pressure liquid chromatography-mass spectrometry for fast and high resolution metabolomics separations

LC-MS is an important tool for metabolomics due its high sensitivity and broad metabolite coverage. The goal of improving resolution and decreasing analysis time in HPLC has led to the use of 5 – 15 cm long columns packed with 1.7 – 1.9 µm particles requiring pressures of 8 – 12 kpsi. We report on the potential for capillary LC-MS based metabolomics utilizing porous C18 particles down to 1.1 µm diameter and columns up to 50 cm long with an operating pressure of 35 kpsi. Our experiments show that it is possible to pack columns with 1.1 µm porous particles to provide predicted improvements in separation time and efficiency. Using kinetic plots to guide the choice of column length and particle size, we packed 50 cm long columns with 1.7 µm particles and 20 cm long columns with 1.1 µm particles, which should produce equivalent performance in shorter times. Columns were tested by performing isocratic and gradient LC-MS analyses of small molecule metabolites and extracts from plasma. These columns provided approximately 100,000 theoretical plates for metabolite standards and peak capacities over 500 in 100 min for a complex plasma extract with robust interfacing to MS. To generate a given peak capacity, the 1.1 µm particles in 20 cm columns required roughly 75% of the time as 1.7 µm particles in 50 cm columns with both operated at 35 kpsi. The 1.1 µm particle packed columns generated a given peak capacity nearly 3 times faster than 1.7 µm particles in 15 cm columns operated at ~10 kpsi. This latter condition represents commercial state of the art for capillary LC. To consider practical benefits for metabolomics, the effect of different LC-MS variables on mass spectral feature detection was evaluated. Lower flow rates (down to 700 nL/min) and larger injection volumes (up to 1 µL) increased the features detected with modest loss in separation performance. The results demonstrate the potential for fast and high resolution separations for metabolomics using 1.1 µm particles operated at 35 kpsi for capillary LC-MS.

Suspect and non-target screening of reuse water by large-volume injection liquid chromatography and quadrupole time-of-flight mass spectrometry

Eight samples were obtained to characterize the chemical loads in water recycled for reuse applications. The sources included stormwater, rooftop runoff, wastewater, mixed water, and drinking water as a comparison. The water was reused for irrigation, cleaning, toilet flushing, and cooling purposes. Large-volume injection (650 μL) high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry were employed to separate and detect features by suspect and non-target screening. The instrumental method had the advantage that no sample extractions were required prior to analysis. Two chromatographic methods were developed to separate positive- and negative-ionizing compounds and retention time models were developed for both. Retention time models provide an additional measure of confidence for probable and tentative identifications. The two models had predictive R2—which indicates how well the models predicts new observations—of 0.87. After data-reduction, the number of features detected in the samples ranged from 304 to 1513. Feature metrics such as the average response-per-feature provided a simple method to characterize similarities and differences between samples. Additionally, a statistical comparison was performed by principal component analysis. Of the 97 suspect-screening compounds, 20 were positively identified. Benzotriazole/benzothiazole-derivatives and per- and poly-fluoroalkyl substances were the most frequently detectedcompounds during suspect screening. Other compounds detected included pharmaceuticals, drug metabolites, and sucralose. Features were prioritized for non-target analysis based on in-house library matches, magnitude of response, and frequency of occurrence. Fifty-five unique compounds were positively identified via non-target analysis. The identified compounds included 17 pharmaceuticals, 17 pesticides, 13 industrial compounds, four personal-use compounds, and four biological compounds.

Development of a solventless stir bar sorptive extraction/thermal desorption large volume injection capillary gas chromatographic-mass spectrometric method for ultra-trace determination of pyrethroids pesticides in river and tap water samples

AbstractStir bar sorptive extraction (SBSE) has been developed in 1999 to efficiently extract and preconcentrate volatile compounds, and many applications have been found after that. This technique conforms to the principles of green chemistry. Here, we used an autosampler with an online thermal desorption unit connected to CGC-MS to analyze pesticides. This study describes the development of a highly sensitive extraction method based on SBSE for simultaneous determination of ultra-trace amounts of four pesticides λ-cyhalothrin, α-cypermethrin, tefluthrin, and dimefluthrin in environmental water samples. This method was compared to the standard liquid–liquid extraction. In this study, a totally solventless SBSE was applied to river and tap water samples for the extraction and preconcentration of four pesticides. PDMS-coated SBSEs of 10 mm × 1 mm thickness were used for this purpose, and SBSEs were directly placed into a large-volume injector of a CGC-MS for thermal desorption of the analytes. In all extractions, deltamethrin was used as an internal standard. This method showed linearity in the range of 1.0–200.0 ng L−1 for cyhalothrin, tefluthrin, and dimefluthrin and 10.0–800 ng L−1 for cypermethrin. Preconcentration factors of 179, 7, 162, and 166 were obtained with very low limits of detection of 0.32, 3.41, 0.36m and 0.69 ng L−1 for cyhalothrin, cypermethrin, tefluthrinm and dimefluthrin, respectively. These detection limits are thousands of times lower than that of the standard method of liquid–liquid extraction. Reproducibility of the method, based on the relative standard deviation, was better than 7.5% and recoveries for spiked tap and river water samples was within the range of 87.83–114.45%. The application of PDMS-coated SBSE coupled with CGC-MS equipped with a large volume injector thermal desorption unit can be used for ultra-trace analysis of environmental water samples. Solventless SBSE offers several advantages over conventional traditional liquid–liquid extraction such as being very fast and economical and provides better extraction without requiring any solvents; so it can be considered as a green method for the analysis of pesticides.

Hypercalcemia After Cosmetic Oil Injections: Unraveling Etiology, Pathogenesis, and Severity.

Intramuscular injections of paraffin oil can cause foreign body granuloma formation and hypercalcemia. Macrophages with the ability to produce high levels of 1,25(OH)2 D3 may induce the mineral disturbance, but no major series of patients have been published to date. Here, medical history, physical evaluation, biochemical, and urinary analysis for calcium homeostasis were obtained from 88 males, who 6 years previously had injected paraffin or synthol oil into skeletal muscle. Moreover, granuloma tissue from three men was cultured for 48 hours ex vivo to determine 1,25(OH)2 D3 production supported by qPCR and immunohistochemistry of vitamin D metabolism and immune cell populations after treatment with 14 different drugs. The 88 men were stratified into men with hypercalcemia (34%), whereas normocalcemic men were separated into men with either normal (42%) or suppressed parathyroid hormone (PTH) (24%). All men had high calcium excretion, and nephrolithiasis was found in 48% of hypercalcemic men, 22% of normocalcemic men with normal PTH, and 47% of normocalcemic men with suppressed PTH. Risk factors for developing hypercalcemia were oil volume injected, injection of heated oil, high serum interleukin-2 receptor levels, and high urine calcium. High 1,25(OH)2 D3 /25OHD ratio, calcium excretion, and low PTH was associated with nephrolithiasis. The vitamin D activating enzyme CYP27B1 was markedly expressed in granuloma tissue, and 1,25(OH)2 D3 was released in concentrations corresponding to 40% to 50% of the production by human kidney specimens. Dexamethasone, ketoconazole, and ciclosporin significantly suppressed granulomatous production of 1,25(OH)2 D3 . In conclusion, this study shows that injection of large oil volumes alters calcium homeostasis and increases the risk of nephrolithiasis. Hypercalciuria is an early sign of disease, and high granulomatous 1,25(OH)2 D3 production is part of the cause. Prospective clinical trials are needed to determine if ciclosporin, ketoconazole, or other drugs can be used as prednisolone-sparing treatment. © 2020 American Society for Bone and Mineral Research (ASBMR).

Development of a simple liquid chromatography method for dissolution testing of low dose desogestrel and ethinylestradiol tablets

Accurate quantitation of low dose, multi-active dissolution samples poses unique challenges in the pharmaceutical industry, often resulting in separate HPLC methods for each active or the use of multiple detectors for increased sensitivity. In this study, we report a fast, isocratic HPLC method utilizing only UV detection for dissolution testing of low dose desogestrel and ethinylestradiol tablets. Rapid separation is completed in 5 min using isocratic elution at a flow rate of 0.45 mL/min, with a column temperature at 30 °C, an injection volume of 50 μL and the detection wavelength at 200 nm. After extensive method development and optimization, the cyano stationary phase was used to overcome the large difference in hydrophobicity for desogestrel and ethinylestradiol, providing balanced retention for both analytes under isocratic elution. Chromatography modeling software was used to provide a rapid analysis of multiple columns and chromatography conditions. The optimized method boasts fast and efficient separation through use of a short, small I.D. column and a large injection volume of dissolution solution to achieve high sensitivity. The stable baseline from an isocratic separation allows low detection wavelengths to be used, resulting in accurate and precise quantitation of both desogestrel and ethinylestradiol. The method has been successfully validated for specificity, linearity, accuracy and precision in the range of 75 – 600 ng/mL for desogestrel and 10 – 80 ng/mL for ethinylestradiol using both HPLC and UHPLC systems. The method robustness was characterized using a design of experiment approach, and the operational design region of the method was established.

Tissue Resistance during Large-Volume Injections in Subcutaneous Tissue of Minipigs.

Injection devices for administration of biopharmaceuticals enable subcutaneous self-administration by patients. To meet patient specific capabilities, injection forces need to be characterized. We address the open question of whether tissue resistance significantly contributes to overall injection forces, especially for large injection volumes. Subcutaneous tissue resistance was systematically quantified for injection volumes up to 11mL depending on viscosity (1-20mPa·s) and injection rates (0.025-0.2mL/s) using Göttingen Minipigs as the animal model. The contribution of an artificially applied external force at the injection site simulating autoinjector needle cover depression was tested between 2.5-7.5N. Tissue resistance reached average values of ~120mbar for injection volumes up to 11mL independent of viscosity and injection rate, and maximum values of 300mbar were determined. Artificially applied external forces led to higher values, independent of the absolute applied force - maximum values of 1bar were obtained when injecting 4.5mL of the 20mPa·s solution at an injection rate of 0.1mL/s with the application of an artificial 5N force, corresponding to ~450mbar. All conditions yield defined injection sites suggesting tissue resistance is defined by mechanical properties of the subcutaneous tissue. We set our results in relation to overall injection forces, concluding that maximum values in tissue resistance may cause challenges during subcutaneous injection when using injection devices. Graphical abstract.

Determination of size-segregated polycyclic aromatic hydrocarbon and its nitro and alkyl analogs in emissions from diesel-biodiesel blends

There have been several works on criteria emissions from biofuels and their mixtures. In this study, the focus is on emissions of non-criteria pollutants, in particular polycyclic aromatic hydrocarbons (PAHs) and their nitrated (nitro-PAHs) and alkylated analogs (alkyl-PAHs). The determinations were made using a standard engine from the fleet of vans used in Brazilian towns and cities operating at 700, 1200 and 1500 rpm and with pure commercial diesel and mixtures of 7, 10, 15 and 20% biodiesel. Sampling was performed with a 10-stage cascade impactor and the selected items were grouped into coarse, fine, ultrafine and nano particles. Chemical analyses were conducted using gas phase chromatography - mass spectrometry (GC MS) detection with large volume injection. The results show that emissions from all PAHs increase with engine speed by 18.1% from 700 to 1200 rpm and by 88.7% from 700 to 1500 rpm. It was observed that there was a reduction of total PAHs from 700 to 1500 rpm when there was an increase in biodiesel content. However, this has the undesirable effect of increasing the nitro-PAHs when there is a greater amount of biodiesel in the mixture, which may be because the rise in NOx emissions can cause a reaction with PAHs. High correlations were observed between the emissions of PAHs and alkyl-PAHs (0.90) and between PAHs and nitro-PAHs (0.67) which suggests the formation mechanisms of these compounds might be similar.

Fractionated stir bar sorptive extraction using conventional and solvent-assisted approaches for enhanced identification capabilities of aroma compounds in beverages.

For successful profiling of aroma carriers in food samples, a highly efficient extraction method is mandatory. A two-step stir bar sorptive extraction (SBSE) approach, namely fractionated SBSE (Fr-SBSE), was developed to improve both the organoleptic and the chemical identification of aroma compounds in beverages. Fr-SBSE consists of two multi-SBSE procedures (mSBSE) performed sequentially on the same sample. The first extraction consists of a conventional mSBSE using three polydimethylsiloxane (PDMS) stir bars (1stmSBSE). This is followed by a solvent-assisted mSBSE performed on the same sample using three solvent-swollen PDMS stir bars (2nd SA-mSBSE). The 1stmSBSE mainly extracts apolar/medium polar solutes with log Kow values >2, while the 2nd SA-mSBSE mainly extracts polar solutes with log Kow values <2. After this two-step fractionation procedure, either thermal desorption (TD) or liquid desorption - large volume injection (LD-LVI), followed by GC-MS is performed on each set of three stir bars. A real-life sample of roasted green tea was used for method development. The performance of the Fr-SBSE method is further illustrated with sensory evaluations and GC-MS analysis for a stout beer sample. Compared to an extraction procedure with SA-mSBSE only, Fr-SBSE including a 1stmSBSE and a 2nd SA-mSBSE reduced co-elution of aroma compounds in the chromatograms and was capable of providing improved mass spectral quality for identification of 17 additional compounds in roasted green tea, and 12 additional compounds in stout beer, respectively. Moreover, odor description and characterization were clearly improved.

Inhibition of Aquaporin 4 Decreases Amyloid A\u03b240 Drainage Around Cerebral Vessels

Aquaporin-4 (AQP4) is located mainly in the astrocytic end-feet around cerebral blood vessels and regulates ion and water homeostasis in the brain. While deletion of AQP4 is shown to reduce amyloid-β (Aβ) clearance and exacerbate Aβ peptide accumulation in plaques and vessels of Alzheimer’s disease mouse models, the mechanism and clearing pathways involved are debated. Here, we investigated how inhibiting the function of AQP4 in healthy male C57BL/6 J mice impacts clearance of Aβ40, the more soluble Aβ isoform. Using two-photon in vivo imaging and visualizing vessels with Sulfurodamine 101 (SR101), we first showed that Aβ40 injected as a ≤ 0.5-μl volume in the cerebral cortex diffused rapidly in parenchyma and accumulated around blood vessels. In animals treated with the AQP4 inhibitor TGN-020, the perivascular Aβ40 accumulation was significantly (P < 0.001) intensified by involving four times more vessels, thus suggesting a generalized clearance defect associated with vessels. Increasing the injecting volume to ≥ 0.5 ≤ 1 μl decreased the difference of Aβ40-positive vessels observed in non-treated and AQP4 inhibitor-treated animals, although the difference was still significant (P = 0.001), suggesting that larger injection volumes could overwhelm intramural vascular clearance mechanisms. While both small and large vessels accumulated Aβ40, for the ≤ 0.5-μl volume group, the average diameter of the Aβ40-positive vessels tended to be larger in control animals compared with TGN-020-treated animals, although the difference was non-significant (P = 0.066). Using histopathology and ultrastructural microscopy, no vascular structural change was observed after a single massive dose of TGN-020. These data suggest that AQP4 deficiency is directly involved in impaired Aβ brain clearance via the peri-/para-vascular routes, and AQP4-mediated vascular clearance might counteract blood-brain barrier abnormalities and age-related vascular amyloidopathy.

Analytical method development for α-amanitin and β-amanitin in plasma at ultra-trace level by online solid phase extraction-high performance liquid chromatography-triple quadrupole mass spectrometry and its application in poisoning events

α-Amanitin and β-amanitin are the main fatal mushroom toxins. The toxins metabolize rapidly in blood and are reported hard to be detected 24 h after poisoning. The main challenge is that of developing a highly sensitive method at sub-pg mL−1 level in blood to diagnose intoxication cause and to study the poisoning mechanism and blood toxicity kinetics. An analytical method for α-amanitin and β-amanitin at ultra-trace level was developed in this study by online solid phase extraction-high performance liquid chromatography-triple quadrupole mass spectrometry (online SPE-LC–MS/MS). Simple protein precipitation and liquid-liquid extraction were introduced to resolve the sample preparation problem of the online SPE-LC–MS/MS system with large-volume injection. A quick valve-switching technique with a quantitative loop as interface was used in the online system. This design can ensure the independence of flow path and pressure between the SPE and LC–MS/MS modules and can obtain the precise cleanup of the toxins. The limits of detection for α-amanitin and β-amanitin in plasma were both 0.02 ng mL-1. The linear ranges were 0.05–20 ng mL-1 with a correlation coefficient r >0.99. The average recoveries at three spiking levels were 82.9 %–92.2 % with the relative standard deviations (RSD) of 5.4 %–8.0 % for α-amanitin and 84.5 %–93.9 % with RSDs of 4.5 %–7.8 % for β-amanitin. The composition and concentration of the toxins in plasma from 18 patients in 5 mushroom poisoning events caused by aminitins were studied. The developed method has high positive confirmation ability and can identify toxins in plasma 40 h after poisoning.

Unexpected Bone Resorption in Mentum Induced by the Soft-Tissue Filler Hyaluronic Acid: A Preliminary Retrospective Cohort Study of Asian Patients.

As one of the most commonly used soft-tissue fillers, hyaluronic acid is generally considered safe and efficacious. However, evident bone resorption in mentum was observed. In this study, the authors analyzed the impact of hyaluronic acid on bone resorption in mentum and the influencing factors. The authors retrospectively compared the computed tomographic scans of patients with or without mentum augmentation using hyaluronic acid. The body mass index- and sex-matched control group was selected randomly. Semimandibular bone resorption index was calculated as the ratio of bone thickness in the incisive fossa to that in the mandibular symphysis. Injection volume, injection interval, the number of injections, product, complication were also recorded. From January of 2014 to June of 2019, 80 patients (160 cases) and 80 controls were recruited. The bone resorption index in the hyaluronic acid injection cohort was significantly lower than in the controls (75.25 ± 10.02 versus 82.86 ± 6.38; p = 0.000). Patients injected with greater than or equal to 1 ml per time were more susceptible to bone erosion compared with patients injected with less (68.89 ± 10.84 versus 76.49 ± 9.42; p = 0.000). There was no significant difference between one- versus multiple-injection groups and short-injection-interval versus long-injection-interval (≥6 months) groups. Furthermore, no reduced aesthetics were realized. Hyaluronic acid injection could induce bone resorption in the mentum; nevertheless, the aesthetics were not impaired. The severity of the bone loss was positively correlated with the injection volume per time; therefore, large-volume injection of hyaluronic acid should be performed with caution. The patients should be fully informed about this complication preoperatively. Therapeutic, III.

Excess pore water pressure caused by the installation of jet grouting columns in clay

Abstract The injection of large volumes of pressurized water and grout into the subsoil during jet grouting generates a sudden increase in excess pore water pressure. This study proposes a theoretical approach to evaluate the variation in excess pore water pressure caused by the installation of a jet grouting column in clay, accounting for the chronological sequence of construction. The jet grouting column installation is simulated through the undrained expansion of a series of spherical cavities. Partial dissipation during the construction process is considered due to the gradual installation of the grouting columns. The relationship between the ultimate cavity radius (au) and the radius of the jet grouting column (rc) is established to represent the influences of both jetting parameters and soil properties on the generated excess pore water pressure. The proposed model is validated using two case studies, one conducted in Singapore marine clay and the other in Shanghai soft clay.

Development of a highly sensitive liquid chromatography–mass spectrometry method to quantify plasma leukotriene E4 and demonstrate pharmacological suppression of endogenous 5-LO pathway activity in man

Low basal endogenous concentrations (<20 pg/mL) of the 5-lipoxygenase (5-LO) pathway biomarker leukotriene E4 (LTE4) in human plasma present a significant analytical challenge. Analytical methods including liquid chromatography–mass spectrometry and enzyme linked immunosorbent assays have been used to quantify plasma LTE4 in the past but have not provided consistent data in the lower pg/mL-range. With our new method, a detection limit (<1 pg/mL plasma) significantly below basal levels of LTE4 was achieved by combining large volume sample purification and enrichment by anion-exchange mixed mode solid phase extraction (SPE) with large volume injection followed by chromatographic separation by ultra performance liquid chromatography (UPLC) and quantification by highly sensitive negative-ion electrospray tandem mass spectrometry (MS/MS). The method was reproducible, accurate and linear between 1 and 120 pg/mL plasma LTE4. The method was used to perform an analysis of plasma samples collected from healthy volunteers in a Phase 1 study with the FLAP (5-lipoxygenase activating protein) inhibitor AZD5718. Basal endogenous LTE4 levels of 5.1 ± 2.7 pg/mL were observed in healthy volunteers (n = 34). In subjects that had been administered a single oral dose of AZD5718, significant suppression (>80%) of plasma LTE4 level was observed, providing pharmacological evidence that endogenous 5-LO pathway activity could be assessed.

Transverse sinus injections drive robust whole-brain expression of transgenes.

Convenient, efficient and fast whole-brain delivery of transgenes presents a persistent experimental challenge in neuroscience. Recent advances demonstrate whole-brain gene delivery by retro-orbital injection of virus, but slow and sparse expression and the large injection volumes required make this approach cumbersome, especially for developmental studies. We developed a novel method for efficient gene delivery across the central nervous system in neonatal mice and rats starting as early as P1 and persisting into adulthood. The method employs transverse sinus injections of 2-4 μL of AAV9 at P0. Here, we describe how to use this method to label and/or genetically manipulate cells in the neonatal rat and mouse brain. The protocol is fast, simple, can be readily adopted by any laboratory, and utilizes the widely available AAV9 capsid. The procedure is adaptable for diverse experimental applications ranging from biochemistry, anatomical and functional mapping, gene expression, silencing, and editing.

Nano-liquid chromatography combined with a sustainable microextraction based on natural deep eutectic solvents for analysis of phthalate esters.

The separation of 11 phthalic acid ester (PAEs) was carried out by nano-liquid chromatography coupled to ultraviolet and MS detection. Preliminary experiments were achieved in order to select suitable stationary phases and chromatographic conditions. The baseline separation was obtained, for all compounds, with an XBridgeTM C18 column in less than 15min, working in step gradient mode. The sensitivity of the method was improved by on-column focusing. PAEs were extracted from alcoholic and nonalcoholic beverages using vortex-assisted emulsification dispersive liquid-liquid microextration and natural deep eutectic solvents. The whole method was validated in terms of linearity, sensitivity, precision, recovery, and repeatability. Combination of both off-line sample preparation preconcentration and large injection volume led to obtain LOQs in the range 5-47ng/mL. The developed nano-LC-UV method was extended to MS detection to confirm the presence of PAEs in some beverages commercialized in different types of packaging.

Translational Feasibility of Lumbar Puncture for Intrathecal AAV Administration

Preclinical studies have demonstrated that a single injection of an adeno-associated virus (AAV) vector into the cerebrospinal fluid (CSF) can achieve widespread gene transfer throughout the central nervous system. Successfully translating this approach to humans requires identifying factors that influence AAV distribution in the CSF so that optimal parameters can be replicated in the clinic. In the context of developing a motor neuron-targeted gene therapy for spinal muscular atrophy, we conducted studies in nonhuman primates to evaluate the impact of injection volume on spinal cord transduction after AAV delivery via lumbar puncture. Lumbar injection of an AAVhu68 vector targeted motor neurons throughout the spinal cord, but only in juvenile nonhuman primates administered large injection volumes, equivalent to about half of the total CSF volume. Upon repeating this study with clinically relevant injection volumes and larger animals, we found that lumbar puncture failed to achieve significant transduction of the spinal cord. In contrast, vector administered into the cisterna magna distributed reproducibly throughout the spinal cord in both juvenile and adult animals. These findings highlight the challenges of translating AAV delivery via lumbar puncture to humans and suggest that delivery into the cisterna magna may represent a more feasible alternative.

Efficiency and safety of peripheral regional anesthesia application in urgent traumatology

In Ukraine, more than 4.5 million people sustain injuries of varying severity annually, and damage to extremities constitutes 60–65 % in the structure of traumatism. Patients with traumatic limb injuries require effective anesthesia / analgesia at an early stage. An urgent anesthesia should provide a sufficient relaxation of the extremity, adequate operative and postoperative pain management and should be safe for patients of different age groups. Peripheral regional anesthesia meets the requirements indicated, but there are a number of outstanding issues: difficulties in identifying plexuses and nerves, high rate of complications. Neither a larger injection volume of local anesthetic nor plexuses and nerves identification using a neurostimulator solves the problem completely. At the same time, ultrasound-guided nerve block does not have the weaknesses mentioned and its use is increasingly covered in literature. The purpose of this work is to analyze the effectiveness and safety of the ultrasound-guided nerve block of the extremities in urgent traumatology. Material and methods. Cases of isolated mechanical traumatic injuries of the limbs in patients who were at the clinical base of the Department of Disaster Medicine, Military Medicine, Anesthesiology and Intensive Care of Zaporizhzhia State Medical University from 2016 to 2018 were analyzed. The average age of the trauma patients was 62.5 (47.0; 82.5) years with a body weight of 78.7 (64.3; 94.6) kg. All the patients underwent ultrasound-guided nerve block using an ultrasound device Logiq E with a standard 12 MHz linear array transducer or the “classical” method (anatomical landmark and paraesthesia technique of plexus location). Anesthesia was performed with 0.5 % bupivacaine at a dose of 1–2 mg/kg. Analgesia was performed with a solution of propofol at 1.5–2.0 mg/kg /h with the addition of ketamine at 1–2 mg/kg/h in case of need. The level of analgesia was evaluated on the Ramsay sedation scale. The study analyzed the duration of plexus and nerves location, block onset time, the duration of motor and sensory block; hemodynamics monitoring with the help of UM-300 monitor at the study stages; complications were recorded. Statistical analysis of the data included descriptive statistics methods. When the values did not follow a normal distribution, these data were expressed as a median (lower quartile; higher quartile). Mann-Whitney U test was used to compare variables; the categorical data were analyzed by Chi-square test with Yates correction and Fischer's exact test. In all statistical calculations, P < 0.05 was the level of significance. Data processing was performed using Statistica 10.0 software. Results . The ultrasound-guided method of plexus and nerves location was faster than the “classical” method by paresthesia (3.8 (2.8; 4.3) min and 7.2 (4.2; 9.4) min, respectively; P = 0.001). But the method of plexus and nerves location did not influence the block onset time and the motor and sensory block duration. However, the level of analgesia in patients with ultrasound-guided nerve block (according to the Ramsay sedation scale) at the III and IV study stages was lower than in those with the “classical” method by paresthesia (3.2 (2.4; 3.7 ) and 5.4 (3.8; 5.7) points, respectively; P = 0.027), indicating a greater efficiency of ultrasound-guided plexus and nerve sensory block. The absence of statistically significant changes in hemodynamic parameters at the study stages indicated an effective intraoperative analgesia in patients with ultrasound-guided nerve block which was complicated in 6 cases (6.0 %). But the “classical” method of plexus and nerve block by paresthesia was complicated in 16 cases (32.0 %). Therefore, the ultrasound-guided method of plexus and nerve block was safer. Thus, it can be concluded that ultrasound-guided location of plexuses and nerves was faster than paresthesia method (3.8 (2.8; 4.3) min and 7.2 (4.2; 9.4) min, respectively; P = 0.001) in urgent traumatology. The sensory block in patients according to the analgesia level on the Ramsay sedation scale at the III and IV study stages was lower as compared to the “classical” method by paresthesia (3.2 (2.4; 3.7) and 5,4 (3.8; 5,7) points, respectively, indicating a more effective ultrasound-guided block of plexuses and nerves. Ultrasound-guided block was effective for intraoperative analgesia based on hemodynamic parameters in urgent traumatology. The method of ultrasound-guided block of plexuses and nerves was safer (6.0 % of complications versus 32.0 % when using the “classical” method by paresthesia).

Coupling of large volume injection with flow modulated two-dimensional gas chromatography

The coupling of large volume injection (LVI) with comprehensive two-dimensional gas chromatography (GC × GC) can be a powerful technique in the analysis of trace-level complex samples. The coupling of LVI and GC × GC using a cost efficiently operable pneumatic modulator based on capillary flow technology has been examined. The aim was to optimize the LVI parameters in the case of samples with compounds covering a wide boiling range. For the optimization of LVI 25 microliters of a solution containing 27 target compounds modelling the composition and the boiling range of diesel oils was used. The injection parameters were evaluated for peak shapes, reproducibility and peak volumes relative to peak volumes obtained using cold splitless injection. For all GC × GC experiments a non-polar first column (Rxi-5ms) and a polar second column (HP-INNOWax) were applied. Through extensive method optimization solvent vent proved to be an unsuitable technique for the injection of compounds covering a wide boiling range: at lower vent times peaks split, while higher vent times caused severe losses of highly volatile compounds. Therefore, a split-splitless LVI method was optimized. Injection speed, split vent time, splitless vent time and vent flow during split vent have been optimized. The developed method is suitable for the coupling of LVI with flow modulated GC × GC. Using the optimized split-splitless LVI parameters no peak distortion of the target compounds was observed. The relative peak volumes were between 60–120% for all compounds (80–120% for 13 compounds).

Fully Automated Determination of Trimellitic Anhydride in Saturated Polyester Resins Using Programmed Temperature Vaporization-Large Volume Injection-Gas Chromatography Previous Aqueous Derivatization with Triethyloxonium Tetrafluoroborate

Trimellitic anhydride (TMAn) is an essential starting material of the chemical manufacturing industry; it is widely used in saturated polyester resins (SPR) manufacturing to produce plasticizers for different purposes. TMAn was recently added, as a new substance of very high concern, to the candidate list by the European Chemicals Agency, since it can lead to sensitization, respiratory tract irritation and lung disease. Any substance from the list of candidates if present in manufactured products at concentrations above 0.1% (w/w) obliges the manufacturer to communicate this to customers down the supply chain and to consumers. We propose here a method that allows the fully automated determination of TMAn in SPR samples by using large volume injection (LVI), with programmed temperature vaporization (PTV) injection, in a gas chromatographic (GC) system equipped with ion trap mass spectrometer (IT) operating in tandem mass spectrometry (MS/MS). The method optimization was obtained by a chemometric model, using the experimental design. Introducing the use of short chromatographic column, triethyloxonium tetrafluoroborate (TEO) as derivatization agent and IS granted specificity, sensitivity and robustness. The detection and quantification limits for TMAn were 0.01% and 0.03% w/w, respectively. Trueness (between 94 and 98%) and precision (RSD lower than 10%, n = 6) were also assessed.

New efficient methodology for screening of selected organic micropollutants in raw- and drinking water from 90 Swedish water treatment plants

A new, efficient method for analysis of organic micropollutants (OMPs) in water samples was developed, validated and applied in a nationwide survey. The goal with the survey was to identify common compounds with relatively high concentrations to be used as markers e.g. for routine monitoring of removal efficiencies. The method comprises sample concentration by evaporation, and large volume injection on a standard UHPLC-MS/MS system. The OMPs selected for this approach were mainly semi-polar and non-volatile, with molecular weights below 300 Da. Except one outlier, the limit of detection (LoD) ranged from 0.01 to 1 ng/L which is sufficient for most surface waters, and also useful for many ground waters. The method requires low manual labor and comparably small sample volumes, enabling a cost-efficient nationwide screening.Raw- and drinking water from 90 Swedish water treatment plants (WTPs) were investigated for occurrence of the selected OMPs. Carbamazepine and tramadol were the most widespread compounds, detected in around 50% of the surface waters. Ground water from rock aquifers were least contaminated, while soil aquifers were more similar to surface waters. Due to the frequent use of ground water in Sweden, many samples did not contain any of the investigated compounds (i.e. below LoD). In the positive samples, the median estimated concentrations of individual OMPs were generally <1 ng/L in raw water and <0.5 ng/L in drinking water. Swedish waters were in general less contaminated than those investigated in similar Brazilian, Chinese, pan-European and US studies.Altogether, the presented methodology gave a cost-efficient overview on the occurrence and estimated concentrations of OMPs in raw- and drinking water on a national level in Sweden. From the data, WTPs can find suitable OMPs to monitor at their site, for example for measuring removal efficiencies on a routine basis.