chromatographic parameters
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Pharmacia ◽  
2022 ◽  
Vol 69 (1) ◽  
pp. 15-20
Author(s):  
Alexandrina Mateeva ◽  
Lily Peikova ◽  
Magdalena Kondeva-Burdina ◽  
Maya Georgieva

In this research, a new rapid PR- HPLC method was developed for the determination of metabolites in isolated rat hapatocytes. The chromatographic parameters, including the stationary and mobile phases, outlet pressure, temperature and flow rate, were optimized. The method identified two initial from the synthesis molecules in higher concentration and one new unidentified structure as products of the hepatocytic processing of the evaluated analyte. The results identified as first step of metabolism the hydrolysis of the hydrazone group. Further investigations should be aimed into determining the next metabolic transformations, predicted by the in silico application of the web server SMARTCyp.


2021 ◽  
Vol 1 (1) ◽  
pp. 75-83
Author(s):  
Benmalek BOULESNAM ◽  
Fahima HAMI ◽  
Djalal TRACHE ◽  
Toudert AHMED ZAID

The growing threat of terrorism in many parts of the world has called for the urgent need to find rapid and reliable means of analyzing explosives. This is in view to help forensic scientists to identify different swabs from post-blast debris. The present study aims to achieve an efficient separation and identification of a mixture of sixteen explosive compounds (including nitroaromatics, nitramines, and nitrate esters) by high performance liquid chromatography using a diode array detection (HPLC/DAD) and an Agilent Poroshell 120 EC-120 C18 column at two wavelengths (235 and 214 nm). Relevant chromatographic parameters such as capacity factors, resolution, selectivity and number of theoretical plates have been optimized in order to achieve the best separation of the different components. In this respect, the effects of various parameters such as gradient time, column temperature, flow rate of mobile phase and initial percentage organic mobile phase on the separation of these compounds were investigated. It was revealed that the method allowed a fairly acceptable separation of all the compounds in less than 15 minutes except for two isomers, namely 4-A-2,6-DNT, 2-A-4,6-DNT and 2,6- DNT which could not be resolved by the used C18 column. This shortcoming notwithstanding, the developed method produced satisfactory results and demonstrated sensitive and robust separation, furthermore indicating that the HPLC developed method can be both fast and efficient for the analysis of complex mixtures of explosive compounds.


2021 ◽  
Vol 40 (1) ◽  
pp. 29
Author(s):  
Suzana Apostolov ◽  
Gyöngyi Vastag

Preliminary assessment of the bioactive profile of azo derivatives was performed applying drug-likeness rules. As the presumed criteria of lipophilicity chromatographic parameters (RM0, m and C0) were calculated in mixtures water/ methanol and water/ acetonitrile by using reversed phase thin-layer chromatography (RPTLC C18/ UV254s). The relationships between chromatographic parameters and relevant software parameters of biological activity of azo derivatives were examined by linear regression and by two multivariate methods. Good linear relationships for each applied system were obtained. The multivariate methods show similarity of the chromatographic parameters (RM0, C0) with standard measure of lipophilicity and pharmacokinetic predictors. The chromatographic parameter m obtained in the same conditions exhibits better agreement with the drug-likeness and toxicity parameters. On the values of azo derivatives’ bioactivity parameters the polarity of the substituent has higher impact than its electronic effects.


Author(s):  
EVA TEJADA ◽  
JANIS VELLA SZIJJ ◽  
MIRIANA CACHIA ◽  
PAULINE FALZON ◽  
LILIAN M AZZOPARDI ◽  
...  

Objective: During reversed-phase high-performance liquid chromatography (HPLC) analyses, optimization of separation can be achieved by selecting appropriate chromatographic conditions. The retention time, peak shape, and peak size of chromatographic peaks are dependent on amount of organic modifier in the mobile phase and buffer pH. The aim of this study was to investigate the effects of varying pH, acetonitrile composition and flow rate of the mobile phase, and temperature of the stationary phase and wavelength in the development of a method to separate Δ9 tetrahydrocannabinol, cannabidiol, and cannabinol. Methods: Mobile phases with different buffer pHs and acetonitrile composition were used with ultraviolet (UV) detection wavelength of 220 nm and 228 nm. The AUPs and retention times were observed using different mobile phase flow rates and stationary phase temperatures. Results: The best results were obtained when using a mobile phase composition of 20% phosphate buffer pH 2.5 or pH 3 and 80% acetonitrile v/v at a flow rate of 2 mL/min at 220 nm. Conclusion: This rapid and easy-to-use HPLC method describes the effect of changing important chromatographic parameters on separation and retention time of cannabinoids and can be effectively applied for high throughput analysis.


2021 ◽  
Vol 5 (1) ◽  
pp. 004-012
Author(s):  
E Ibrahim Adel ◽  
Elhenawee Magda ◽  
Saleh Hanaa ◽  
M Sebaiy Mahmoud

This literature review is concerning with liquid chromatography specifically high performance liquid chromatography (HPLC), Ultra high performance liquid chromatography (UHPLC), chromatography theory, chromatographic parameters, monolithic columns, principles of green chemistry and its application ingreen chromatography.


Author(s):  
Suo Decheng ◽  
Fan Xia ◽  
Wei Shulin ◽  
Li Yang

Abstract A simple and sensitive method was proposed for choline, carnitine, acetylcarnitine (ACa) and acetylcholine (ACh) separation in feed, blood and urine of animals by using ion chromatography (IC) and detection by tandem mass spectrometry (MS/MS). Analytes were extracted using a mixture of acetonitrile and water, purified by C18 solid-phase extraction columns, separated via IC with an IonPac SCS-1 column and detected by an MS/MS detector by using isotopic internal standards for quantification. The effects of different chromatographic parameters on the separation were also investigated. Under optimal conditions, the recovery was >90%, with the relative standard deviations of <15%. The proposed method was highly reliable for the simultaneous determination of choline, carnitine, ACa and ACh in feed, blood and urine.


2021 ◽  
Vol 14 (2) ◽  
pp. 147
Author(s):  
Anna W. Sobańska ◽  
Jeremy Robertson ◽  
Elżbieta Brzezińska

Several chromatographic parameters (RM0 and S obtained from RP-18 TLC with methanol—pH 7.4 phosphate buffer mobile phases by extrapolation to zero concentration of methanol; Rf and RM obtained from RP-18 TLC with acetonitrile—pH 7.4 phosphate buffer 70:30 v/v as a mobile phase) and calculated molecular descriptors (molecular weight—MW; molar volume—VM; polar surface area—PSA; total count of nitrogen and oxygen atoms—(N+O); H-bond donor count—HD; H-bond acceptor count—HA; distribution coefficient—log D; total energy—ET; binding energy—Eb; hydration energy—Eh; energy of the highest occupied molecular orbital—EHOMO; energy of the lowest unoccupied orbital—ELUMO; electronic energy—Ee; surface area—Sa; octanol-water partition coefficient—log P; dipole moment—DM; refractivity—R, polarizability—α) and their combinations (Rf/PSA, RM/MW, RM/VM) were tested in order to generate useful models of solutes’ skin permeability coefficient log Kp. It was established that neither RM0 nor S obtained in the conditions used in this study is a good predictor of the skin permeability coefficient. The chromatographic parameters Rf and Rf/PSA were also unsuitable for this purpose. A simple and potentially useful, purely computational model based on (N+O), log D and HD as independent variables and accounting for ca. 83% of total variability was obtained. The evaluation of parameters derived from RM (RM, RM/MW, RM/VM) as independent variables in log Kp models proved that RM/VM is the most suitable descriptor belonging to this group. In a search for a reliable log Kp model based on this descriptor two possibilities were considered: a relatively simple model based on 5 independent variables: (N+O), log D, RM/VM, ET and Eh and a more complex one, involving also Eb, MW and PSA.


Author(s):  
A Stajić ◽  
J Janković-Maksić ◽  
B Jančić-Stojanović ◽  
M Medenica

Abstract Vancomycin and teicoplanin are glycopeptide antibacterials that inhibit the bacteria cell wall synthesis showing activity against gram-positive bacteria. Development of the sensitive method is of great importance for quality control of these drugs that are fermentation products. Modification of the fermentation conditions could cause the differences in the relative amount of the total substance or component, as it is the case with teicoplanin. The main objective of this study was development of the sensitive and effective ultra high performance liquid chromatography - tandem mass sprectrometry (UHPLC-MS/MS) method for simultaneous quantification of vancomycin, all six subcomponents of teicoplanin, and its pharmacopoeial impurity A in pharmaceutical forms. The scientific-based Quality by Design approach was implemented in the MS and UHPLC method development. Detection and quantification of analytes were carried out in positive electrospray ion mode by multiple reaction monitoring. Capillary voltage, cone voltage and collision energy were optimized by implementing experimental design methodology and optimal values for each fragment ion were obtained by performing experiments according to ‘Rechtschaffen’ design matrix. An ACQUITY CSH Phenyl-hexyl (2.1 × 50 mm, particle size 1.7 μm) column was chosen for the separation under the gradient elution mode with the mobile phase consisted of 0.1% formic acid in water (mobile phase A) and acetonitrile (mobile phase B). Optimal gradient elution parameters were achieved by applying ‘Rechtschaffen’ design too. Method operable design regions were constructed for investigated MS and chromatographic parameters. The method was fully validated, and its applicability was confirmed throughout the ability to follow the behavior of vancomycin and teicoplanin under stress conditions.


Author(s):  
Preksha Patel ◽  
Manan Raval ◽  
Nidhi Patel ◽  
Samir Patel ◽  
Niraj Vyas ◽  
...  

Abstract Background Roots of Argyreia speciosa (Linn. F) Sweet (family: Convolvulaceae) are used in Ayurveda to treat male reproductive and nervous system disorders. Objective Isolation of scopoletin from the roots of Argyreia speciosa, development and validation of an analytical method using HPLC for the quantification of scopoletin from the root powder of Argyreia speciosa. Method Scopoletin was isolated from chloroform fraction prepared from hydrolyzed methanolic extract and identified using spectral studies. A reverse-phase HPLC based analytical method was developed and optimized using the DoE approach to estimate scopoletin from the roots of Argyreia speciosa. Scopoletin was separated and quantified using HPLC containing C18 column and a PDA detector. The optimized mobile phase was methanol: water (pH∼3.2) [25: 75, %v/v]. Results The Box-Behnken design was used to optimize chromatographic parameters and the extraction procedure. The validation studies showed a linear relationship (r2=0.998) in the range of 1–40 µg/ml. The limit of Detection and Limit of Quantification were found to be 0.28 µg/ml and 0.84 µg/ml, respectively and the recovery values were found between 91.94 to 97.86%. The developed analytical method was found robust too. The amount of scopoletin was estimated to be 0.024 ± 0.0016%w/w from dried root powder. Conclusion The recorded chromatogram and amount of scopoletin determined would serve as one of the standardization parameters to access the quality of raw material containing Argyreia speciosa. Highlights Developed analytical method may be adopted as a part of the standardization procedure for Argyreia speciosa in the quality control laboratory.


2021 ◽  
Vol 14 (1) ◽  
pp. 60-65
Author(s):  
Laura Jánovová ◽  
Katarína Hroboňová

Abstract Lactic acid is a biologically important organic acid existing in two enantiomeric forms which are differently metabolized in the human body. In this paper, direct chiral separation of lactic acid by high performance liquid chromatography is presented. Five chiral stationary phases based on macrocyclic antibiotics were used for enantioseparation and chromatographic parameters, such as retention factors, resolution and selectivity factors, were determined under different column temperatures ranging from 5 to 45 °C. Optical isomers of lactic acid were efficiently separated using chiral stationary phases based on teicoplanin (R S = 1.9 ) and ristocetin (R S = 1.7 ) in reversed-phase separation mode at the column temperature of 25 °C.


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