scholarly journals Extraction sample preparation for chromatographic determination of residual quantities of acidic penicillins in milk

2021 ◽  
Vol 57 (3) ◽  
pp. 286-293
Author(s):  
A. G. Polonevich ◽  
S. M. Leschev ◽  
A. I. Palianskikh ◽  
L. L. Belyshava
Keyword(s):  
Sample Preparation ◽  
Ammonium Sulfate ◽  
Chromatographic Determination ◽  
Distribution Coefficients ◽  
Penicillin G ◽  
Salting Out ◽  
Agent Based ◽  
Residual Content ◽  
Acid Type

The distribution of six acid-type penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, nafcillin, dicloxacillin) in the extraction systems of chloroform–aqueous solutions of ammonium sulfate was studied. The reported distribution coefficients values of penicillins demonstrated the effectiveness of using ammonium sulfate as a salting-out agent. Based on the data obtained, a procedure for milk sample preparation was developed for the quantification of the residual content of six acid-type penicillins.

scholarly journals Comparison of two sample preparation procedures for HPLC determination of ochratoxin A

2009 ◽  
Vol 61 (4) ◽  
pp. 639-644 ◽  
Author(s):  
Gorica Vukovic ◽  
Snezana Pavlovic ◽  
M.S. Ristic
Keyword(s):  
Sample Preparation ◽  
Phosphoric Acid ◽  
Ochratoxin A ◽  
Chromatographic Determination ◽  
Liquid Extraction ◽  
Immunoaffinity Column ◽  
Maize Flour ◽  
Liquid Liquid Extraction ◽  
Immunoaffinity Columns

In preparation of samples for chromatographic determination of ochratoxin A, two types of columns were used for sample cleanup (SPE and immunoaffinity columns). The first method consisted of liquid-liquid extraction with a mixture of chloroform and phosphoric acid, followed by ion-exchange cleanup on Waters Oasis MAX columns. The sec?ond method consisted of extraction with a mixture of water and methanol, followed by LCTech OtaCLEAN immunoaf?finity column cleanup. Recoveries of the methods were determined at three levels in three repetitions for maize flour, and they were 84% (%RSD = 19.2) for the first method of sample preparation and 101% (%RSD = 2.2) for the second method. Values of LOQ for OTA were 0.25 and 1.00 ?g/kg for the IAC and SPE clean-up procedures, respectively. Both methods comply with present regulations, but the MAX sample clean-up procedure should be used as an alternative, since the immunoaffinity column clean-up procedure is characterized by better reproducibility, accuracy, and efficiency.

scholarly journals INTERPHASE DISTRIBUTION OF SOME AMINO ACIDS IN EXTRACTION SYSTEMS BASED ON N-VINYLFORMAMIDE COPOLYMERS

2019 ◽  
Vol 62 (1) ◽  
pp. 4-10 ◽  
Author(s):  
Nadezhda Ya. Mokshina ◽  
Oksana A. Pakhomova ◽  
Gennadiy V. Shatalov ◽  
Irina I. Kosinova
Keyword(s):  
Amino Acids ◽  
Radical Copolymerization ◽  
Distribution Coefficients ◽  
Water Soluble ◽  
Separate Determination ◽  
Buffer Solution ◽  
Salting Out ◽  
Interphase Distribution ◽  
Degree Of Extraction

The extraction characteristics of amino acids and mono-amides of acids were studied using copolymers of N-vinylformamide with 1-vinyl- and 1-methacryloyl-3,5-dimethylpyrazole as extractants. Synthesis of water-soluble copolymers was carried out by radical copolymerization in dioxane with thermoinitiation with dinitro-azobisisomoic acid. The distribution coefficients and the degree of extraction of analytes for a single extraction in the presence of a salting out agent are calculated. To determine the representatives of amino acids, the method of capillary electrophoresis was used. The most effective extraction systems for the extraction of amino acids and monoamides of acids are proposed: the intrinsic viscosity of polymers, the concentration of polymer and analyte solution, the ratio of phase volumes, the ratio of the mole fractions of N-vinylformamide to 1-vinyl and 1-methacryloyl-3,5-dimethylpyrazole. The results of the most effective interfacial distribution of lysine between a water-salt solution and an extractant are presented, which is a copolymer of N-vinylformamide with 1-methacryloyl-3,5-dimethylpyrazole. The concentration of the copolymer and the ratio of the volumes of equilibrium phases at which the maximum degree of lysine extraction is reached are established. A copolymer of N-vinylformamide with 1-vinyl-3,5-dimethylpyrazole is used for simultaneous extraction of cystine, asparagine and glutamine. The established extraction characteristics allowed a successful separate determination of the amino acid cystine and monoamides (asparagine and glutamine) in a joint presence in an aqueous solution. When choosing the conditions for separate electrophoretic determination of amino acids, the optimal composition of the buffer solution, the type and concentration of the micelle was found. The dependence of the structure of the analytes on their interphase distribution was established, and the complexing power of the copolymers of N-vinylformamide with 1-vinyl- and 1-methacryloyl-3,5-dimethylpyrazole was revealed with respect to the representatives of amino acids. The extraction systems used on the basis of N-vinylformamide copolymers are distinguished by ecological and economic expediency, good metrological indices.

scholarly journals Analysis of melatonin and serotonin from cherries: a review

2018 ◽  
Vol 22 (1) ◽  
pp. 52-60
Author(s):  
Varga-Visi Éva ◽  
Ildikó Jócsák ◽  
Katalin Lóki ◽  
György Végvári
Keyword(s):  
Sample Preparation ◽  
Electrochemical Detection ◽  
Sweet Cherry ◽  
Sour Cherry ◽  
Chromatographic Determination ◽  
Fluorometric Detection ◽  
Liquid Chromatographic Determination ◽  
Special Respect ◽  
Liquid Chromatographic

The proper quantification of serotonin and melatonin in different foods is indispensable to evaluate the significance of their dietary intake on blood and plasma levels in humans. This review summarizes the issues regarding the measurements of these compounds from sour cherry and sweet cherry. Sample preparation and analytical methods are discussed, mainly focusing on the liquid chromatographic determination of these compounds, with special respect to their parallel determination in one run. Keywords: indoleamine derivatives, LC-MS, electrochemical detection, fluorometric detection

Direct Blood-Injection Method for Gas Chromatographic Determination of Alcohols and Other Volatile Compounds

1971 ◽  
Vol 17 (2) ◽  
pp. 82-85 ◽  
Author(s):  
Naresh C Jain
Keyword(s):  
Sample Preparation ◽  
Volatile Compounds ◽  
Low Cost ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Chromatograph ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Blood Injection

Abstract An extremely simple, rapid method is described for simultaneously determining methanol, ethanol, acetone, isopropanol, and low-boiling hydrocarbons associated with glue sniffing. Less than 1 µl of blood, mixed with an internal standard, is injected directly into a low-cost gas chromatograph equipped with a flame-ionization detector. No extraction, distillation, and (or) sample preparation is required, and the method is sensitive to less than 10 µg of alcohol per ml.

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