scholarly journals Express determination of cephalexin

2021 ◽  
Vol 21 (3) ◽  
pp. 260-266
Author(s):  
Anastasiia V. Tumskaia ◽  
◽  
Irina V. Kosyreva ◽  
Keyword(s):  
Detection Limit ◽  
Linear Dependence ◽  
Quantitative Assessment ◽  
Heating Time ◽  
Test Methods ◽  
Test Method ◽  
Optimal Conditions ◽  
Antibiotic Concentration ◽  
Blue Channel

Test means based on immobilized Fehling’s reagent for the determination of cephalexin have been obtained. Methods for visual and colorimetric assessment of antibiotic concentration using a smartphone camera have been developed. The optimal conditions for the indicator reaction have been selected with varying heating time and temperature. For a visual semi-quantitative assessment of the content of cephalexin, a color scale has been obtained. The metrological characteristics of the test method have been determined: the range of the determined contents is 0.5–16 mg/ml, the unreliability interval is 0.1–0.4 mg/ml, and the detection limit is 0.4 mg / ml. For the colorimetric assessment of the concentration of cephalexin, a linear dependence of the intensity of the Blue channel on the logarithm of the concentration of cephalexin (у = –96x + 144, r 2 = 0.99) has been constructed, and linear dependences of the area (у = –36986x + 62458, r 2 = 0.96) and perimeter (у = –270x + 786, r 2 = 0.93) from the logarithm of the concentration of cephalexin have been obtained. The range of the determined contents was 0.1–16 mg/ml, the lower limit was 0.1 mg / ml. The verification of the correctness of the developed test methods was carried out by the «introduced-found» method (Sr  0.13).

scholarly journals APPLICATION OF MATHEMATICAL PLANNING OF THE EXPERIMENT IN THE CHOOSING THE OPTIMUM CONDITIONS OF THE VAPOR-PHASE GAS-CHROMATOGRAPHIC DETERMINATION OF FORMALDEHYDE IN THE URINE

2018 ◽  
Vol 97 (10) ◽  
pp. 985-989 ◽  
Author(s):  
Аnton N. Alekseenko ◽  
O. M. Zhurba
Keyword(s):  
Mathematical Model ◽  
Vapor Phase ◽  
Statistical Processing ◽  
Analytical Signal ◽  
Heating Time ◽  
Gas Extraction ◽  
Optimal Conditions ◽  
Steep Ascent ◽  
The Mathematical Model

Introduction. There was substantiated a method for the determination of formaldehyde by vapor-phase gas chromatography by the use of derivatizing reagent o-(2,3,4,5,6-pentafluorbenzyl)hydroxylamine. Material and methods. Formaldehyde in urine was derivatized to o-pentafluorobenzyloxime and recovered to the vapor phase by heating the urine sample with o-(2,3,4,5,6-pentafluorbenzyl)hydroxylamine in a sealed vial. Gas-chromatographic analysis of the vapor-air phase was performed in a mode of the temperature gradient on a capillary column HP-5 with a flame ionization detector. Identification of the analyte in the form of the derivative-o- pentafluorobenzyloxime of formaldehyde was carried out according to the absolute retention time, which was established by comparing the chromatograms of model formaldehyde mixtures in the urine of different concentrations. Results. The optimal conditions for gas extraction are selected using mathematical experimental planning. The most important factors of gas extraction in the vapor-phase analysis are the temperature and time of the establishment of the interphase equilibrium with heating. From the experimentally obtained curves of the analytical signal on the temperature and the heating time, the zero level and the interval of variation of these factors are chosen. A matrix for planning a 2-factor experiment was constructed. The coefficients of the mathematical model are determined. There was carried out statistical processing of the experimental data, which was reduced to the estimation of the reproducibility of the optimization parameter and to the evaluation of the significance of the coefficient of the mathematical model. The adequacy of the mathematical model was evaluated, its interpretation was carried out. Discussion. The peak area of the analyte increases with the elevating the temperature and heating time, due to an increase in the analyte concentration in the vapor phase. Moreover, the heating time makes a greater contribution to the formation of the analytical signal than the temperature. The step of motion along the gradient was calculated and the experiments of steep ascent were carried out. Conclusion. According to the results of the steep ascent experiments, the optimal conditions for the gas extraction of formaldehyde in the form of a derivative were chosen.

Study on the Bearing Capacity Test for the Saline Soil Soft Ground

2014 ◽  
Vol 587-589 ◽  
pp. 947-951
Author(s):  
Jun Yong Liu ◽  
Liu Jun Zhang
Keyword(s):  
Bearing Capacity ◽  
Saline Soil ◽  
Test Methods ◽  
Test Method ◽  
Soft Ground ◽  
Characteristic Value ◽  
Soft Foundation

The test methods provided by current related "specifications" do not apply to saline soil soft foundation bearing capacity test. Through discussing the limitations of the related specifications and based on the experience on saline soil soft ground capacity test, the paper made some improvements of test on such aspects: conditions of loading and stopping load, determination of the characteristic value of the ground bearing capacity and evaluation, the paper also put forward the saline soil soft ground capacity test method.

scholarly journals Determination of Ca3(PO4)2 in Bone China by Microwave Digestion-ICP-AES

2021 ◽  
Vol 245 ◽  
pp. 03088
Author(s):  
Zheng-gen Huang ◽  
He-ying Yi ◽  
Tao Wang ◽  
Lian-ying An ◽  
Xiao-bin Zhao
Keyword(s):  
Detection Limit ◽  
Tricalcium Phosphate ◽  
Microwave Digestion ◽  
Test Method ◽  
National Standard ◽  
Good Precision ◽  
Test Results ◽  
Established Method ◽  
Bone China

The establishment of a microwave digestion method with the advantages of simple operation and complete digestion to process samples has shown that, high sensitivity, wide linear dynamic range, good precision, fast analysis speed and many other advantages of ICP-AES technology for rapid determination of tricalcium phosphate in bone china. Through the use of different P2O5 content of phosphate rock and kaolin national standard material configuration standard working solution for matrix matching to eliminate matrix interference, the microwave digestion sample processing condition selection, coexisting ion interference, method precision, accuracy, and detection limit tests were carried out. The results showed that the detection limit of the newly established method for tricalcium phosphate is 0.011mg.L-1; the HCl-HNO3-HF-H2O2 mixed acid decomposition system dissolves the best samples; the interference of the test results through the matrix matching coexisting ion pair is small; The relative standard deviation (RSD) is 1.08%~4.64%, and the recovery rate of standard addition is 92.4%~107.9%. The established method has high accuracy and precision; the bone china samples are analyzed and compared with the conventional digestion national standard method The t test method is used to prove that the two methods are not significantly different from the test results.

scholarly journals Analysis of Vitamin A in Multivitamin Products

2021 ◽  
Vol 11 (3) ◽  
pp. 174-184
Author(s):  
A. S. Alekseeva ◽  
T. B. Shemeryankina ◽  
M. N. Lyakina ◽  
M. S. Smirnova ◽  
E. P. Fedorova ◽  
...  
Keyword(s):  
Vitamin A ◽  
High Performance ◽  
Beta Carotene ◽  
Test Methods ◽  
Retinyl Palmitate ◽  
Test Method ◽  
Medicinal Products ◽  
Retinyl Acetate ◽  
Preliminary Purification

Vitamin A is present in multivitamin products mainly in the form of retinol esters: retinyl acetate, retinyl palmitate, and beta carotene—retinol precursor (dimer) found in plants, which is capable of converting into retinol in liver cells. Retinol is determined in medicinal products primarily by high performance liquid chromatography (HPLC), with preliminary purification and vitamin isolation by liquid-liquid extraction. However, scientific literature also describes other methods of sample preparation and analysis of such compounds. An important issue is differentiation of vitamin A from other fat-soluble vitamins often included as components in multivitamin products. The aim of the study was to analyse and summarise data on current methods used for determination of vitamin A and its derivatives in medicinal products. The authors analysed the range of vitamin A products authorised in the Russian Federation, and the test methods described in their product specification files. The study demonstrated that the test method most often used for determination of retinol esters was HPLC with isocratic elution mode using octadecylsilyl packing in the reverse-phase mode, and, less frequently, aminopropylsilyl packing in the normal phase mode. Determination of beta carotene in medicinal products is most often performed using spectrophotometry. 

scholarly journals Determination of Sulfamethazine in Milk by Biosensor Immunoassay

1999 ◽  
Vol 82 (6) ◽  
pp. 1316-1320 ◽  
Author(s):  
Valérie Gaudin ◽  
Marie-Laure Pavy
Keyword(s):  
Polyclonal Antibodies ◽  
Gold Surface ◽  
Cross Reactivity ◽  
Antibody Concentration ◽  
Optimal Conditions ◽  
Maximum Residue Limit ◽  
Antibiotic Concentration ◽  
Flow Rates ◽  
Carboxymethyl Dextran

Abstract A biosensor based on surface plasmon resonance (SPR) measurement was developed for use in an immunoassay for detection of sulfamethazine (SMZ) in milk. The biospecific surface was a carboxymethyl dextran¯modified gold-surface sensor chip to which SMZ was covalently bound. The assay was based on inhibition of the binding of polyclonal antibodies to immobilized SMZ by SMZ in the sample. The SPR response changed inversely in relation to the antibiotic concentration in the sample. Calibration curves were constructed for SMZ in buffer and in milk at a concentration which included the maximum residue limit (0 to 200 μg/kg). The analysis time per sample varied from 8 to 30 min. Different flow rates and antibodies were modified alternatively during the study to assess their influence on the performance of the assay. The active antibody concentration was calculated at approximately 1880 and 180 nM for the antibody anti-SMZ 1 and the antibody anti-SMZ 2, respectively. No cross-reactivity of antibodies with other antibiotics was found. Under optimal conditions, the detection limits in milk for SMZ were 8 and 1.7 μg/kg, respectively, for antibody 1 and antibody 2, at a flow rate of 20 μL/min.

The modern methods of pin-type bearing test of metallic materials

2019 ◽  
Vol 85 (7) ◽  
pp. 41-49
Author(s):  
Yaroslava V. Sulimina ◽  
Nikolay O. Yakovlev ◽  
Vladimir S. Erasov ◽  
Aleksey Yu. Ampilogov ◽  
Andrey N. Polyakov ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Test Procedure ◽  
Test Methods ◽  
Test Method ◽  
Strength Characteristics ◽  
Metallic Materials ◽  
Bearing Strength ◽  
Bearing Stress ◽  
The Impact

The special features of various bearing deformation measurements for pin-type bearing tests of metallic materials are considered along with their impact on the magnitude of the «bearing elastic modulus» and bearing stress. These bearing test methods are present in ASTM and various institutional standards, though no state standard (GOST, GOST R) is currently available for bearing test method of metallic materials. Analysis of additional deformations which arise in determining the degree of hole bearing deformation is carried out. A set of sources of additional deformations is shown to be characteristic for each test procedure and is attributed to the design features of the device, the site and a way of mounting the extensometer. Additional deformations can be both tensile and compressive. It is shown that the impact of additional deformations on the «bearing elastic modulus» is limited to 14% for different procedures. No difference between the methods is revealed with regard to determination of the strength characteristics. At the same time the dispersion decreases with increase in plastic deformation and for bearing deformation about 4% the variation coefficient for all methods is no more than 1%. Advantages and shortcomings of the bearing test methods which affect the reproducibility of the results are considered. The effect of the specimen geometry on the bearing characteristics is considered. It is shown that increase both in the distance from the edge of the bearing specimen to the center of the hole for 1163T, VT6ch, 30KhGSA alloys and residual bearing deformation up to 6%, increase bearing strength characteristics.

Fan Performance Testing Using Inlet Measuring Methods

1973 ◽  
Vol 187 (1) ◽  
pp. 405-412
Author(s):  
J. Whitaker
Keyword(s):  
Flow Measurement ◽  
Performance Testing ◽  
Test Methods ◽  
Test Method ◽  
Fan Performance ◽  
Optimum Configuration ◽  
Free Discharge ◽  
Pressure Selection ◽  
Selection Of

To contend with installation variants the fan must be tested in a system that resembles its site installation. Four simplified system arrangements are covered with two inlet test methods—ducted inlet and free inlet—by adding ducts to the free discharge. With free inlet tests a plenum chamber is attached to the fan inlet in order to obtain the required measurements; investigations to provide information concerning the optimum configuration of this test method are described. Determination of static pressure, selection of inlet devices for flow measurement; simulation of inlet and outlet ducts and the method of loading are also discussed.

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