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Gas Chromatographic Analysis
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Margosis and Tsuji [2,21] collaborated on this difficult analysis. Since the stereoisomers, neomycins B and C, have different therapeutic effects, it is important that the analysis include separate assays of the two. In reviewing earlier work, Margosis found poor correlation of values reported for neomycin C and excessive solvent tailing. After close and critical examination of the procedure, the authors arrived at several improvements, the most spectacular a redesign of the injection port. The original design of the instrument involved an inlet sleeve. Between it and the column was a joint with Teflon and brass exposure. The Margosis-Tsuji redesigned port eliminated the junction. The brass barrier was drilled out and a modified column placed in the instrument so that the injection area walls were all glass. Following that, good correlation was obtained for assays of neomycin C.
The Fatty Acid Perfused Isolated Working Heart
Published in John H. McNeill, Measurement of Cardiovascular Function, 2019
Rick L. Barr, Gary D. Lopaschuk
The system should also contain an injection port so that drugs or chemicals of interest can be introduced into the system. During perfusions that do not require a radioisotope label, drugs or chemicals may be introduced simply by lowering the buffer reservoir and pipetting the agent into the buffer in the reservoir. This does involve some risk as the heart may accidentally be touched. The heart may then see an extremely high concentration of the drug. Also, opening the system does allow the heart to cool somewhat, which is obviously not desirable. The injection port is far more practical and easier to use and is recommended to be used during cold perfusions also. Then take a fast tracing on the physiograph and label it as the first time point. If flow measurements, such as cardiac output or oxygen consumption are required, record these now on the tracing.
Insulin Therapy for Diabetes: Current Scenario and Future Perspectives
Published in Debarshi Kar Mahapatra, Sanjay Kumar Bharti, Medicinal Chemistry with Pharmaceutical Product Development, 2019
Yogesh A. Kulkarni, R. S. Gaud, Mayuresh S. Garud
Two years after the discovery of insulin, in 1924, specifically designed syringe for the insulin injection was developed by Becton, Dickinson and Company (USA) [41]. In the early days, the metals and/or glass were used to make syringes. These syringes were reusable and after sterilizing by boiling them. Later in 1954 first glass disposable syringes were introduced to reduce the incidence of needle associated infections [42]. After that numerous changes have been made to insulin syringes to get it in the present form. But despite all changes, syringes has disadvantage of inducing the pain which makes them less patient-friendly. Less accuracy is another disadvantage of using syringes [43]. To overcome these disadvantages, an injection port has been made available by Medtronic, known as i-port Advance®. It combines an injection port and an inserter in one complete set that eliminates the need for multiple injections without puncturing the skin for each dose [44].
Evaluation of blood BTEX levels in fuel stations workers using vortex-assisted dispersive liquid-liquid microextraction based on deep eutectic solvent followed by gas chromatography flame-ionization detector
Published in Toxin Reviews, 2023
Mari Ataee, Toraj Ahmadi Jouybari, Hawre Lateef Ahmed, Hadi Ahmadi Jouybari, Meghdad Pirsaheb, Nazir Fattahi
The analysis of BTEX compounds was performed with a Shimadzu GC 2010 system equipped with split/splitless injection and a flame-ionization detector (FID). The GC was fitted with a BP-5 capillary column (30 m × 0.22 mm i.d., coated with a 0.25 μm film of 95% methyl, 5% phenyl copolymer) from SGE (Victoria, Australia). Ultra-pure helium (99.9999%, Air Products, West Sussex, UK), passed through a molecular sieve trap and an oxygen trap (Chromatography Research Supplies, Louisville, USA), was used as carrier gas at a constant linear velocity of 30 cm s−1. The injection port was held at 200 °C and used in splitless mode with a splitless time 0.5 min. The analysis was performed with an initial oven temperature of 30 °C, held for 3 min and followed by heating to 100 °C at 10 °C min−1 (held for 1 min). The temperature of FID was maintained at 300 °C.
Anti-diabetic and hypolipidemic effects of Cinnamon cassia bark extracts: an in vitro, in vivo, and in silico approach
Published in Archives of Physiology and Biochemistry, 2023
K. Vijayakumar, B. Prasanna, R. L. Rengarajan, A. Rathinam, S. Velayuthaprabhu, A. Vijaya Anand
Bioactive compounds from the different extract were identified based on the GC retention time. Briefly, about 30 g of dried C. cassia barks sample was soaked and dissolved in 75 ml of ethanol for 24 h. Then, the filtrates are collected by evaporating under liquid nitrogen. The GC-MS analysis was carried out using Perkin-Elmer GC-MS system (Clarus 500, AutoSystem XL, Perkin-Elmer, Waltham, MA) equipped and coupled with turbo mass Gold-Perking Elmer Turbomas 5.2 spectrometer and Elite-1 (100% Dimethylpolysiloxane), 300 m × 0.25 mm × 1 μm df capillary column. The instrument is set to an initial temperature of 110 °C and maintained at this temperature for 2 min. At the end of this period, the oven temperature is raised up to 280 °C at the rate of an increase of 5 °C/min, which maintained for 9 min. The injection port temperature was ensured as 250 °C and helium flow rate as 1 ml/min. The ionisation voltage was set as 70 eV. The samples were injected in split mode as 10:1. Mass Spectral scan rage was set at 45–450 (MHz). The identified GC-MS chemical constituents as a fragmentation pattern of mass spectra were compared with a stored database of the National Institute of Standards and Technology Mass Spectral database (NIST-MS). The matching percentage of each component was calculated from the relative peak area of each compound in the chromatogram (Iordache et al.2009). The identified biologically active phytoconstituents from GC-MS were adapted for docking studies.
Ocimum sanctum, Zingiber officinale, and Piper nigrum extracts and their effects on gut microbiota modulations (prebiotic potential), basal inflammatory markers and lipid levels: oral supplementation study in healthy rats
Published in Pharmaceutical Biology, 2022
Narendra Babu Kondapalli, Rajkumar Hemalatha, Satyanarayana Uppala, Srinivas Reddy Yathapu, Shujauddin Mohammed, Mullapudi Venkata Surekha, Ananthan Rajendran, Dinesh Kumar Bharadwaj
The essentials oil percentage in hydro-alcoholic extracts of O. sanctum, Z. officinale, and P. nigrum alone and combined were analysed by GC-MS method (Agilent-Technologies model 5977). The essential oil chemical constituents of extracts were separated using a HP-5MS capillary column (30 m × 0.25 mm, film thickness 0.25 μm). A sample of 1.0 μL was injected (Split ratio 10:1) on helium as carrier gas at a flow rate of 1.2 mL/min. The initial column temperature was maintained at 50 °C for 2 min, with a programmed increment of 10 °C/min to 280 °C followed by hold at the same temperature for 5 min. The injection port, transfer line and source temperatures were 250 °C, 280 °C, and 230 °C, respectively. For GC-MS detection, an electron impact ionisation mode, with ionisation energy of 70 eV, was used. The different compounds present in the extracts were identified using the National Institute of Standards and Technology (NIST14) mass spectral library.