Processing of experimental data for the separation of chromatographic signals of tetracycline group antibiotics by mathematical modeling

2020 ◽  
Vol 64 (12) ◽  
pp. 52-59
Author(s):  
Aisylu Z. Mukharlyamova ◽  
◽  
Aleksandr M. Saifutdinov ◽  
Elvira R. Rakhmetova ◽  
Aygul G. Mukhammetshina ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
High Performance ◽  
Basic Structure ◽  
Initial Value ◽  
Residual Concentration ◽  
Main Method ◽  
Preparation Conditions ◽  
High Concentrations ◽  
Tetracycline Group

Antibiotics belonging to the classes of sulfonamides, amphenicols and tetracyclines, such as tetracycline, oxytetracycline and chlortetracycline, are used to control infectious diseases of honeybees. In addition, tetracycline group antibiotics can be added directly to plants during flowering. Contamination of the flower with high concentrations of antibiotics entails the risk of transferring antibiotic residues to honey. Consequently, these antibiotics persist as contaminants in honey, and the determination of these drugs in honey samples is of great importance. Tetracyclines have a broad spectrum of activity against gram-positive and gram-negative bacteria. The basic structure of tetracyclines consists of a hydro-naphthacene framework containing four rings. Due to their possible toxic or allergic reactions and the possibility that pathogens may become resistant to these drugs, much attention has recently been paid to tetracyclines. For the detection of residual quantities of antibiotics in food products increasingly requires reliable analytical methods. The main method for determining tetracycline group antibiotics is the method of high-performance liquid chromatography, but the micro-quantities of their residual concentration and unsatisfactory chromatographic conditions, under which peaks may overlap, as well as insufficient sample preparation conditions, under which matrix components may overlap, make quantitative calculations difficult when using this method. This article describes a method for calculating the initial value of intesiveness and peak width using mathematical modeling. Based on the analysis of real chromatographic data, the applicability of this method for the quantitative determination of tetracycline group antibiotics is shown.

scholarly journals Determination of amino acids in human biological fluids by high-performance liquid chromatography: critical review

Amino Acids ◽  
2021 ◽  
Author(s):  
Grażyna Gałęzowska ◽  
Joanna Ratajczyk ◽  
Lidia Wolska
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
High Performance ◽  
Hplc Analysis ◽  
Limit Of Detection ◽  
Biological Fluids ◽  
Analytical Techniques ◽  
Epidemiological Studies ◽  
Preparation Conditions

AbstractThe quantitation and qualification of amino acids are most commonly used in clinical and epidemiological studies, and provide an excellent way of monitoring compounds in human fluids which have not been monitored previously, to prevent some diseases. Because of this, it is not surprising that scientific interest in evaluating these compounds has resurfaced in recent years and has precipitated the development of a multitude of new analytical techniques. This review considers recent developments in HPLC analytics on the basis of publications from the last few years. It helps to update and systematize knowledge in this area. Particular attention is paid to the progress of analytical methods, pointing out the advantages and drawbacks of the various techniques used for the preparation, separation and determination of amino acids. Depending on the type of sample, the preparation conditions for HPLC analysis change. For this reason, the review has focused on three types of samples, namely urine, blood and cerebrospinal fluid. Despite time-consuming sample preparation before HPLC analysis, an additional derivatization technique should be used, depending on the detection technique used. There are proposals for columns that are specially modified for amino acid separation without derivatization, but the limit of detection of the substance is less beneficial. In view of the fact that amino acid analyses have been performed for years and new solutions may generate increased costs, it may turn out that older proposals are much more advantageous.

scholarly journals DETERMINAÇÃO DE GLIFOSATO E ÁCIDO AMINOMETILFOSFÔNICO EM ÁGUAS SUPERFICIAIS DO ARROIO PASSO DO PILÃO

2003 ◽  
Vol 13 ◽  
Author(s):  
MARCELO DUTRA DA SILVA ◽  
MARIA DO CARMO RUARO PERALBA ◽  
MARIA LAURA TURINO MATTOS
Keyword(s):  
High Performance Liquid Chromatography ◽  
Environmental Protection Agency ◽  
High Performance ◽  
Herbicide Application ◽  
Protection Agency ◽  
Brazilian Legislation ◽  
Aminomethylphosphonic Acid ◽  
Glyphosate Herbicide ◽  
High Concentrations

Para investigar a presença do herbicida Glifosato na microbacia hidrográfica arroio Passo do Pilão foram coletadas amostras de água em 15 distintos pontos no arroio Passo do Pilão, nos períodos de 30 e 60 dias após a aplicação do herbicida (DAAH), as quais foram analisadas por cromatografia a líquido de alta eficiência (CLAE). As análises revelaram a presença do herbicida nas águas superficiais dessa microbacia, tanto nas amostras após 30 dias de aplicação do Glifosato como nas de 60 DAAH. Concentrações elevadas (acima de 100 ppb) foram detectadas, principalmente em pontos próximos às áreas de intenso cultivo. As concentrações detectadas foram menores que 500 e 700 ppb, limites de concentrações máximas permitidas para o Glifosato pela legislação brasileira e pela Agência de Proteção Ambiental dos Estados Unidos, respectivamente. DETERMINATION OF GLYPHOSATE AND AMINOMETHYLPHOSPHONIC ACID IN SUPERFICIAL WATERS OF ARROIO PASSO DO PILÃO Abstract To investigation the presence of Glyphosate herbicide in Arroio Passo do Pilão watershed, samples of water were collected in 15 distinct points in Arroio Passo do Pilão, in period of 30 and 60 days after herbicide application (DAHA), which were analysed by high performance liquid chromatography (HPLC). The analysis revealed the presence of the herbicide in superficial areas of this watershed, even in the samples after 30 days of Glyphosate applicatication as in 60 DAHA. High concentrations (above 100 ppb) were detected, mainly in points near to intense cultivation areas. The concentrations detected were smaller than 500 and 700 ppb, limits of the maximum concentrations allowed for Glyphosate by the brazilian legislation and by the Environmental Protection Agency of United States, respectivelly.

scholarly journals Application of IR spectroscopy to control oxidation inhibitor (ionol) concentration in mineral transformer oils

2020 ◽  
Vol 216 ◽  
pp. 01056
Author(s):  
Marsel Sh. Garifullin ◽  
Marina N. Lyutikova ◽  
Adelya R. Kuchkarova ◽  
Azat R. Bikzinurov ◽  
Yuliya N. Solobodina
Keyword(s):  
Gas Chromatography ◽  
Ir Spectroscopy ◽  
Oxidation Process ◽  
Antioxidant Additive ◽  
Residual Concentration ◽  
Main Method ◽  
Transformer Oils ◽  
Gas Chromatographic Method ◽  
Insulating Properties

Mineral insulating oils used as dielectric and heat dissipating agent in high voltage oil-filled equipment are subject to oxidation. Oxidation results in the appearance of undesirable substances that reduce the electrical insulating properties of liquids. Therefore, to inhibit the oxidation process, an antioxidant additive is introduced into transformer oils. In the overwhelming majority, 2,6-di-tert-butyl-4-methylphenol (ionol) is used as an inhibitor. Residual concentration of ionol is a regularly monitored parameter. In Russia, the main method for determining the concentration of ionol in oil is gas chromatography. However, fourier-transform infrared spectroscopy should be considered as an alternative method for monitoring the ionol content as it has a number of advantages over the gas chromatographic method. The paper compares the results of the determination of ionol in operational transformer oils using gas chromatography and the IR method. We justified that the method of IR spectroscopy has no limitations as applied to oils from power transformers equipped with adsorption purification systems.

Liquid-chromatographic determination of 4-aminopyridine in serum, saliva, and urine.

1981 ◽  
Vol 27 (3) ◽  
pp. 437-440 ◽  
Author(s):  
D R Uges ◽  
P Bouma
Keyword(s):  
High Performance ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Drug Concentrations ◽  
Liquid Chromatographic Determination ◽  
High Concentrations ◽  
Liquid Chromatographic

Abstract We have developed "high-performance" liquid-chromatographic methods for determining 4-aminopyridine, an acetylcholine-releasing drug, in serum, saliva, and urine. As little as 1 microgram/L can be detected by extracting the alkalinized sample plus the internal standard (3,4-diaminopyridine) into dichloromethane, mixing the organic phase with 1-pentanol, evaporating the dichloromethane, and injecting the residue onto a reversed-phase column, where it is eluted with acetonitrile/methanol/aqueous ammonium carbonate, with detection at 245 nm. Analytical recoveries from serum averaged 86.7%. The CV at 50 micrograms/L was 2.9% (n = 8). For urine samples containing very high concentrations of 4-aminopyridine, we mixed urine and potassium carbonate in an automatic injector vial, extracted the drug into dichloromethane, centrifuged, and injected an aliquot of the extract into the chromatograph. Analytical recoveries averaged 92%, and the CV was about 2% for drug concentrations of 0.1-8 mg/L of urine.

scholarly journals Determination of Nonylphenol and Its Ethoxylates by HPLC 1100 in Water Environment of Taiyuan City

2019 ◽  
pp. 660-670
Author(s):  
Kouakou Yao Salomon ◽  
Cai Xiang Zhang ◽  
Akpo Kouakou Sylvain ◽  
Yan Xin Wang ◽  
Xiao Ping Liao
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
High Performance ◽  
Water Environment ◽  
Industrial Area ◽  
Shanxi Province ◽  
Human Consumption ◽  
High Concentrations ◽  
Surface And Groundwater

The aim of this work is to study the occurrence of nonylphenol and its ethoxylates in Taiyuan industrial area. The present study has firstly determined best conditions of Nonylphenol and its ethoxylates detection by using High Performance Liquid Chromatography (HPLC) 1100 series, variating solvent, mobile phase and flow: rate. These conditions let secondly the concentration determination of these pollutants in water media. Samples were collected from surface and groundwater in the industrial area of Taiyuan city (Shanxi province). Nonylphenol Ethoxylates (NPEOs) detection was better when solvent and Mobile phase were 2-propanol and Flow rate at 0.1 ml/min. Concentrations of Nonylphenol (NP) and NPEOs found in rivers and wastewaters collectors ranged from 80 to 933 µg/L and 38 to 743 µg/L respectively, while for groundwater, concentrations ranged from 24.6 to 151 µg/L and from 20 to 274 µg/L. These high concentrations found both in surface and groundwater, represent a risk of exposition to endocrine disruptors for humans and aquatic species. Actions should be taken to avoid or reduce the use of those compounds, or industries should apply some treatment before release their wastewater into environment. Attention should be paid especially to groundwater in case of human consumption. Introduction to groundwater way and degradation pathways from surface water to groundwater need to further study.

scholarly journals Improved HPLC Method for the Determination of Moxifloxacin in Application to a Pharmacokinetics Study in Patients with Infectious Diseases

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nan Wang ◽  
Liqin Zhu ◽  
Xuequn Zhao ◽  
Wenjie Yang ◽  
He Sun
Keyword(s):  
Human Plasma ◽  
High Performance ◽  
Room Temperature ◽  
Internal Standard ◽  
Hplc Method ◽  
Single Step ◽  
Pharmacokinetic Studies ◽  
Liquid Liquid Extraction ◽  
High Concentrations

Objective. To develop a simple and rapid high-performance liquid chromatography (HPLC) method for measuring moxifloxacin concentration in human plasma. Methods. Following a single step liquid-liquid extraction, analytes along with an internal standard (IS) were separated using an isocratic mobile phase of 0.1% triethylamine (adjusted pH to 4.8 with phosphoric acid)/acetonitrile (80/20, v/v) at flow rate of 1 mL/min on reverse phase Kromasil C18 column (250 mm × 4.6 mm, 5 μm) at room temperature. Results. Total analytical run time for selecting moxifloxacin was 15 min. The assays exhibited good linearity (r2=0.9998) over the studied range of 25 to 5000 ng/mL. The absolute recovery rate of low, medium, and high concentrations were 69.88%, 78.86%, and 78.51%, respectively. The relative recovery rates were 98.50%, 96.61%, and 101.79%, respectively. Coefficient of variation and error at both of the intraday and interday assessments were less than 4.7%. Conclusions. The results indicated that this method is a simple, rapid, precise and accurate assay for the determination of moxifloxacin concentrations in human plasma. This validated method is sensitive and reproducible enough to be used in pharmacokinetic studies.

Influence of Glucuronosyl Bilirubin and (EZ)-Cyclobilirubin on Determination of Serum Unbound Bilirubin by UB-Analyser

2002 ◽  
Vol 39 (6) ◽  
pp. 583-588 ◽  
Author(s):  
Susumu Itoh ◽  
Kou Kawada ◽  
Takashi Kusaka ◽  
Saneyuki Yasuda ◽  
Hitoshi Okada ◽  
...  
Keyword(s):  
High Performance ◽  
Total Bilirubin ◽  
Enzyme Reaction ◽  
Serum Samples ◽  
Bilirubin Concentration ◽  
Group Iii ◽  
Group I ◽  
Unbound Bilirubin ◽  
High Concentrations

Background In the enzyme reaction for the determination of the unbound (free) bilirubin concentration by glucose oxidase and peroxidase, materials with low affinity for serum protein are reactive. The influence of these materials on the determination of serum unbound bilirubin was investigated. Methods Serum samples from patients with neonatal hyperbilirubinaemia were analysed by high-performance liquid chromatography for total glucuronosyl bilirubin concentration (TGC) and (E2)-cyclobilirubin concentration [(EZ)-C]. Based on these measurements, the samples were classified into three groups: group I [13 samples, TGC < 2 μmol/L and (EZ)-C < 2·5 μmol/L]; group II [four samples, TGC < 2 μmol/L and (EZ)-C ≥ 2·5 μmol/L]; and group III (five samples, TGC ≥ 2 μmol/L). The concentrations of total bilirubin and unbound bilirubin were measured in these same samples with a UB-analyser. When the absorbance at 460 nm was monitored, the decrease in absorbance was non-linear (concave curve). The degree of concavity was estimated (D15 value) as the deviation from linearity at 15 s. Results The D15 value was significantly higher in groups II and III than in group I. D15 value correlated significantly with TGC, (EZ)-C and unbound bilirubin concentration, and the unbound bilirubin concentration correlated significantly with TGC and (EZ)-C. Conclusion These results indicated that determination of serum unbound bilirubin concentration using the UB-analyser could be positively skewed by high concentrations of TGC and (EZ)-C.

Inappropriate Methods for the Emergency Determination of Plasma Paracetamol

1979 ◽  
Vol 16 (1-6) ◽  
pp. 89-95 ◽  
Author(s):  
M. J. Stewart ◽  
P. I. Adriaenssens ◽  
D. R. Jarvie ◽  
L. F. Prescott
Keyword(s):  
High Performance ◽  
Reference Method ◽  
High Performance Liquid Chromatographic ◽  
Positive Error ◽  
Specific Therapy ◽  
Extraction Step ◽  
High Concentrations ◽  
Liquid Chromatographic ◽  
Paracetamol Overdosage

Methods for the estimation of plasma paracetamol which depend on acid hydrolysis to p-aminophenol without a prior extraction step also measure inactive metabolites which are present in high concentrations. The extent of the overestimate obtained with such methods was determined using 24 samples from patients after paracetamol overdosage. There was a positive error of between 40 and 700 % compared with a high-performance liquid chromatographic reference method which measured only unchanged paracetamol. These non-specific methods should not be used to determine the need for specific therapy in patients with paracetamol poisoning.

Determination of urinary norepinephrine and epinephrine by liquid chromatography with fluorescence detection and pre-column derivatization

1990 ◽  
Vol 36 (5) ◽  
pp. 732-736 ◽  
Author(s):  
P Moleman ◽  
J van Dijk
Keyword(s):  
Liquid Chromatography ◽  
Present Method ◽  
High Performance ◽  
Reversed Phase ◽  
Fluorescence Derivatization ◽  
Specificity And Sensitivity ◽  
Low Concentrations ◽  
High Concentrations ◽  
Phase Column

Abstract We assayed norepinephrine and epinephrine by utilizing solvent extraction, fluorescence derivatization, and "high-performance" liquid chromatography. A 100-microL aliquot of urine was extracted twice according to Smedes et al. (J Chromatogr 1982;231:25-39) and subsequently incubated with 1,2-diphenylethylenediamine. A 100-microL aliquot of the resulting mixture was injected into a reversed-phase column, and norepinephrine and epinephrine were detected fluorometrically. The within-day CV was 3.0-4.0% and the between-day CV 3.4-7.1% for normal and high concentrations of both analytes. At low concentrations (15-40 nmol/L) these CVs were 4.2-6.8% and 6.8-9.2%, respectively. The detection limit of the assay was less than 0.4 nmol/L for each analyte. We discuss the critical steps for extraction, derivatization, and chromatography. The present method combines the qualities of high precision, specificity, and sensitivity.

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