scholarly journals Qualitative Simultaneous Identification of Permanent and Hydrocarbon Gases by GC-TCD using Column Coupling Method

2017 ◽  
Vol 5 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Oman Zuas ◽  
Muhammad Rizky Mulyana
Keyword(s):  
Flow Rate ◽  
Coupling Method ◽  
Gas Mixture ◽  
Hydrocarbon Gases ◽  
Column Temperature ◽  
Column Method ◽  
Routine Work ◽  
Single Column ◽  
Simultaneous Identification ◽  
Column Coupling

The potential application of the GC-TCD using column coupling method was investigated by means of comparison with the single column method for the identification of gas mixture containing 5 inorganic and 6 hydrocarbon gases. The results indicate the useful of column coupling method, relative to the single column method. In addition, the flow rate of carrier gas and column temperature on the retention time of the target components have a notice-able effect. Application of the column coupling method for qualitative identification of the targeted components in natural gas samples indicate that the method can be used for routine work.

scholarly journals A New Validated Stability Indicating RP-HPLC Method for Simultaneous Quantification of Formoterol Fumarate Dihydrate and Mometasone Furoate in Metered Dose Inhalation Aerosol

2021 ◽  
Vol 33 (11) ◽  
pp. 2723-2728
Author(s):  
Surya Prakash Mamillapalli ◽  
Gourabattina Lakshmi Prasanna ◽  
B. Venkata Subbaiah ◽  
N. Annapurna
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
Hplc Method ◽  
Mometasone Furoate ◽  
Simultaneous Estimation ◽  
Column Temperature ◽  
Stability Indicating ◽  
Metered Dose ◽  
Formoterol Fumarate ◽  
Dose Inhalation

Stability indicating reversed phase-HPLC method for simultaneous estimation of mometasone furoate (MAF) and formoterol fumarate (FFD) in metered dose inhalation aerosol (MDI) dosage formulation has been developed and discussed in the present work. The chromatographic separation was achieved using Hypersil ODS column (250 mm × 4.6 mm, 3 μm) using an isocratic separation mode at a flow rate of 1.2 mL/min, column temperature of 50 ºC. The system operates with a mobile phase comprising of solution-A (buffer): Solution-B (acetonitrile) mixed in the ratio of 70:30 %v/v at a UV detection wavelength of 214 nm. Retention times of mometasone furoate and formoterol fumarate found to be about 3 min and 7 min, respectively. All possible degradation products of both compounds were monitored at 214 nm and spectral purity along with % mass balance is assessed using PDA detector. Both analyte were subjected to force degradation studies, found all degradants were resolved from analyte peaks and also other process-related impurities. The proposed method is validated for specificity, linearity, accuracy, precision and robustness as per ICH guidelines and found to be adequate. Method stood to be robust with variation in column temperature, flow rate, pH of buffer and organic content in mobile phase.

OPTIMIZATION OF RP-HPLC METHOD BY 32 – CENTRAL COMPOSITE DESIGN FOR THE VALIDATION AND ESTIMATION OF DOXYCYCLINE HYCLATE IN BULK DRUG AND FORMULATIONS

INDIAN DRUGS ◽  
2015 ◽  
Vol 52 (11) ◽  
pp. 42-49
Author(s):  
C Dhal ◽  
◽  
F. J. Ahmad ◽  
M. Singhal ◽  
A. Kukrety ◽  
...  
Keyword(s):  
Central Composite Design ◽  
Flow Rate ◽  
High Performance ◽  
Hplc Method ◽  
Array Detector ◽  
Doxycycline Hyclate ◽  
Chromatography Method ◽  
Column Temperature ◽  
Bulk Drug ◽  
Central Composite

An accurate, sensitive, precise, economic and rapid isocratic Reverse Phase High Performance Liquid Chromatography method was developed complying Quality by Design (QbD) trends and validated for determining doxycycline hyclate in bulk drug, tablet and capsule dosage form. The method was optimized using Minitab software with 3 factors (pH of the buffer, flow rate and percentage of buffer in the mobile phase), 2 level (higher limit and lower limit) Central Composite Design (CCD). The results of randomized 20 runs were analyzed for optimum composite desirability to give optimum conditions such as, pH 6.5, flow rate 0.9 mLmin-1 and 30:70 V/V 0.05M potassium dihydrogen orthophosphate buffer adjusted to pH 6.5 using orthophosphoric acid and methanol using C8 column 250 X 4.6 mm X 5.0 μm, injection volume of 10uL, ambient column temperature and ultraviolet detection using photo diode array detector at 360nm as constants. The method was validated as per ICH guidelines and was found linear over a concentration range of 10-100 μg/mL (r2 = 0.999) with the limits of detection and quantification being 2.45 μg/mL and 7.55 μg/mL respectively.

An Experimental Procedure for Determining Both the Density and Flow Rate From Pressure Drop Measurements in a Cylindrical Pipe

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
Ghislain Michaux ◽  
Olivier Vauquelin ◽  
Elsa Gauger
Keyword(s):  
Reynolds Number ◽  
Flow Rate ◽  
Pressure Change ◽  
Gas Mixture ◽  
Gas Extraction ◽  
Cylindrical Pipe ◽  
Flow Area ◽  
Number Range ◽  
Experimental Procedure ◽  
Pressure Drops

An experimental procedure was developed for determining both the density and flow rate of a gas from measurements of pressure drops caused by an abrupt flow area contraction in a cylindrical pipe. Experiments were carried out by varying the density and flow rate of a light gas mixture of air and helium, spanning a Reynolds number range from 0.2×104 to 3.4×104. From experimental results, a procedure was then proposed for evaluating the density from pressure change measurements in the scope of light gas extraction experiments.

A Gas Chromatographic Column for Pesticide Residue Analysis: Retention Times and Response Data

1966 ◽  
Vol 49 (2) ◽  
pp. 374-385
Author(s):  
Jerry A Burke ◽  
Wendell Holswade
Keyword(s):  
Liquid Phase ◽  
Flow Rate ◽  
Residue Analysis ◽  
Operating Conditions ◽  
The Other ◽  
Pesticide Residue Analysis ◽  
Column Temperature ◽  
Response Data ◽  
Relative Retention ◽  
Injection Temperature

Abstract DC-200 and QF-1 have been combined as the liquid phase in a GLC column to give a different elution of pesticides from the nonpolar methyl silicones now in wide use. The column packing consists of intimately mixed, equal portions of previously coated 80/100 mesh Gas Chrom Q: one portion with 15% QF-1 and the other with 10% DC-200. Operating conditions for a 6 ft × 4 mm i.d. column are as follows: column temperature, 200°C; injection temperature, 225°C; and flow rate, 120 ml N2/min. Relative retention times and response data for electron capture and microcoulometric GLC systems are tabulated for over 85 pesticide chemicals.

Plasma-Enhanced Atomic Layer Deposition of GaN Thin Film at Low Temperature

2017 ◽  
Vol 727 ◽  
pp. 907-914
Author(s):  
Wen Hui Tang ◽  
Yi Jia ◽  
Bo Cheng Zhang ◽  
Chang Wei Yang ◽  
You Zhi Qu ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Low Temperature ◽  
Atomic Layer Deposition ◽  
Flow Rate ◽  
Nitrogen Sources ◽  
Atomic Layer ◽  
Gas Mixture ◽  
X Ray ◽  
Layer Deposition

Polycrystalline GaN thin films were successfully grown at low temperature (250 °C) by plasma-enhanced atomic layer deposition with NH3, N2, N2/H2 gas mixture and trimethylgallium (TMG) as precusor. The growth rate, crystal structure, surface composition and the valence state of the corresponding element of the GaN thin films using different nitrogen sources were characterized and examined systematically via the spectroscopic ellipsometry, the x-ray diffractometer, the x-ray photoel-ectron spectrometer. It is showed that all the GaN thin films using different nitrogen sources were polycrystalline structure and the preffered orientation were mainly (100). The films using N2 and N2/H2 gas mixture had a higher crystal quality than films using NH3. The GPC (growth rate per cycle) would increase with the increase of the N2 flow rate. The films using a suitable ratio of N2/H2 flow rate had not only a high GPC but a good crystal quality. The ratios of Ga/N element of the films using N2/H2 gas mixture were approximated to 1:1, it would increase with the ratio of the N2/H2 flow rate in the gas mixture, which is showing much effect of the ratios of N2/H2 flow rate on the nitrogen content of the thin films.

Spatially Resolved Gain Measurements in a CO2 Amplifier

1972 ◽  
Vol 50 (8) ◽  
pp. 769-777
Author(s):  
A. K. McQuillan ◽  
A. I. Carswell ◽  
K. S. Jammu
Keyword(s):  
Binary Mixtures ◽  
Flow Rate ◽  
Spatial Variations ◽  
Gas Mixture ◽  
Laser Amplifier ◽  
Mixture Flow ◽  
Spatial Intensity ◽  
Spatially Resolved

Spatially resolved gain measurements at 10.6 μm have been made transverse to the discharge in an axially flowing CO2 laser amplifier. The composition of the amplifier medium has been varied to include initially pure CO2, binary mixtures of CO2:CO, CO2:He, and CO2:N2, and triple mixtures of CO2:N2:He. Strong spatial variations of gain are observed which depend on the gas mixture, flow rate, temperature, pressure, and current. Corresponding spatial intensity profiles of the sidelight emission of CO2 at 4.3 μm are shown.

scholarly journals HPLC method for simultaneous determination of impurities and degradation products in Cardiazol

Pharmacia ◽  
2020 ◽  
Vol 67 (1) ◽  
pp. 29-37
Author(s):  
Iryna Drapak ◽  
Borys Zimenkovsky ◽  
Liudas Ivanauskas ◽  
Ivan Bezruk ◽  
Lina Perekhoda ◽  
...  
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
Degradation Products ◽  
Phase 1 ◽  
Simultaneous Detection ◽  
Hplc Method ◽  
Column Temperature ◽  
Degree Of Separation ◽  
Determination Of Impurities

Aim. The aim of study was to develop a simple and accurate procedure that could be applied for the determination of impurities and degradation products in cardiazol. Materials and methods. Separation in samples was carried out with Acquity H-class UPLC system (Waters, Milford, USA) equipped with Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm) (Waters, Milford, USA). Xevo TQD triple quadrupole mass spectrometer detector (Waters Millford, USA) was used to obtain MS/MS data. Mobile phase A: 0.1% solution of trifluoroacetic acid R in water R; Mobile phase B: acetonitrile R. Samples were chromatographed in gradient mode (Table 1). Flow rate of the mobile phase: 1 ml / min. Column temperature: 30 °С. Detection: at 240 nm wavelength. Injection volume: 10 μl. Results. The retention time of the main substance is about 18.5 minutes. The order of the peak, the retention times and relative retention times: impurity B (12.04, 0.65); impurity А (18.5; 0.98); Cardiazol (18.87; 1.00). The LOD and LOQ values obtained were in the range of 30 ng/mL to 100 ng/mL and 80 ng/mL to 310 ng/mL respectively (with respect to sample concentration of 2 mg/ml). Linearity was established in the range of LOQ level to 0.2% having regression coefficients in the range of 0.9996 to 0.9999. The change in the temperature of the column affects the degree of separation of cardiazol and the impurity A, and thus, with a decrease of 5 ° C, the degree of separation is (1.06), while with increasing this index (3.43). When changing the flow rate of the mobile phase, the degree of separation changes in the following order, with a decrease to 0.9 ml / min separation (1.90), with an increase in speed to 1.1 ml / min (2.45). When the number of mobile phase B decreases by 5%, the degree of separation varies by (2.65), with an increase of 5% (1.82). In comparison with the chromatogram of the tested solution, the substance is not resistant to the action of peroxide, alkaline and acid decomposition. Conclusion. 1) HPLC method was developed and validated for the simultaneous detection and quantitation of impurities formed during the synthesis of cardiazol. 2) The method proved to be sensitive, selective, precise, linear, accurate and stability-indicating.

scholarly journals Liquid chromatographic enantioseparation of thalidomide and its derivatives on cyclodextrin-bonded stationary phases

2018 ◽  
Vol 91 (2) ◽  
pp. 99-106
Author(s):  
Szabó-Zoltán István ◽  
Foroughbakhshfasaei Mohammadhassan ◽  
Dobó Máté ◽  
Noszál Béla ◽  
Tóth Gergő
Keyword(s):  
Acetic Acid ◽  
Stationary Phase ◽  
Flow Rate ◽  
Chiral Separation ◽  
Stationary Phases ◽  
Reversed Phase ◽  
Chiral Separations ◽  
Column Temperature ◽  
Bonded Stationary Phases ◽  
Chiral Interactions

Abstract The chiral separation of three racemic immunomodulatory drugs, thalidomide, pomalidomide and lenalidomide was studied, using three cyclodextrin bonded stationary phases (β-, hydroxypropyl-β- and carboxymethyl-β-CD) in reversed-phase and polar organic mode. In polar organic mode, using acetonitrile and methanol, no chiral separation was observed. In reversed-phase mode pomalidomide showed chiral interactions with all selectors, while lenalidomide showed no chiral interactions with any of the cyclodextrins employed. Thalidomide showed chiral interactions with β-and carboxymethyl-β-CD, only. Based on these observations it can be concluded that the oxo group at position two is necessary for chiral recognition, while the aromatic primary amine group enhances it. Orthogonal experimental design was used to investigate the effect of the eluent composition, flow rate, and the column temperature on chiral separation. Concentration of the organic modifier was the most important factor among the investigated three variables showing high impact on the chiral separations. In the case of thalidomide optimized parameters (β-cyclodextrin-based stationary phase, 0.1% acetic acid/acetonitrile 95/5 (v/v), 5 °C column temperature, 0.6 ml/min flow rate) resulted in a resolution of 1.68 ± 0.02 between enantiomers. For pomalidomide, this value was 2.70 ± 0.02, under the circumstances as follows: β-cyclodextrin-based stationary phase, 0.1% acetic acid/acetonitrile 90/10 (v/v), 15 °C column temperature and 0.8 mL/min flow rate. Utilizing the experimental conditions employed on an LC-MS/MS system, concentrations as low as 2 ng/mL could be determined from mouse plasma for both substances. Elution sequences were determined with enantiopure standards and in both cases the R-enantiomers eluted first. The methods developed are suitable for the chiral separation of the abovementioned compounds and are sound starting points for bioanalytical method development.

scholarly journals Computer-Aided Rapid Establishment of Fingerprint of Xiaojin Capsule by HPLC

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hui Jiang ◽  
Yuansheng Xiao ◽  
Xingya Xue ◽  
Hongli Jin ◽  
Yang Xiang ◽  
...  
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Flow Rate ◽  
Column Temperature ◽  
Hplc Fingerprint ◽  
Computer Aided ◽  
Quality Markers ◽  
Short Time ◽  
Unsupervised Cluster Analysis

Traditional Chinese medicine (TCM) formulas have a significant clinical efficacy, and the fingerprint technology has been widely accepted to fully reveal the quality of TCM. Whereas, it is a great challenge to establish the fingerprint chromatogram which can fully reflect every single herb material in a short time. In this study, we used Xiaojin capsule (XJC) as a case and developed a rapid fingerprint method based on increasing the column temperature and flow rate simultaneously combined with computer-aided. First, the elution gradient was optimized based on the retention parameters and peak shape parameters of the four linear gradients, and then, the column temperature and flow rate were increased simultaneously to shorten the analysis time. Next, the standard fingerprint chromatogram of XJC, which can reflect every herb material, was generated. Finally, quality markers were screened through unsupervised cluster analysis and supervised orthogonal partial least squares discrimination analysis. Combining computer-aided with increasing column temperature and flow rate simultaneously can develop the rapid method for establishing HPLC fingerprint of XJC, which can fully reflect every single herb material and provide comprehensive quality control. The strategy for establishing HPLC fingerprint of TCM formula could be applied to other traditional Chinese medicine formulas and herbal medicine.

scholarly journals Rhodamine-B dye removal using aliquat-336 modified amberlite XAD-4 resin in fixed-bed columns in series

2021 ◽  
Author(s):  
Muzaffar Iqbal ◽  
Dipaloy Datta
Keyword(s):  
Flow Rate ◽  
Rhodamine B ◽  
Fixed Bed ◽  
Interaction Mechanism ◽  
Breakthrough Curves ◽  
Aliquat 336 ◽  
Effective Removal ◽  
Single Column ◽  
In Series ◽  
Clark Model

Abstract The present work reports studies on the effective removal of Rhodamine-B (RhB) using Aliquat-336 modified Amberlite XAD-4 resin in the fixed-bed columns in series. The effect of flow rate (Q = 2 to 6 mL·min−1), bed height (h = 3.5 to 7 cm) and initial RhB dye concentration (Cin = 10 to 20 mg·L−1) was studied. When a single column was used, 93% RhB dye was removed in 3 h at Q = 2 mL·min−1, Cin = 10 mg·L−1, and h = 7 cm. When three columns in series were used, almost 100% dye was removed until 80 h. The maximum breakthrough time (142 h) and saturation time (244 h) were found by keeping Q = 2 mL·min−1, h = 7 cm of each column and Cin = 10 mg·L−1. Mathematical modeling of the breakthrough curves was done by using Yoon-Nelson, Clark, Wolborska, and pore diffusion models. The Clark model best fitted the experimental data. The possible interaction mechanism between Aliquat-336 and RhB dye was proposed. The column was regenerated in continuous mode using 1 M HCl solution and maintaining a flow rate of 2 mL·min−1.

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