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1

Determination of theoretical retention times for peptides analyzed by reversed-phase high-performance liquid chromatography

100%
Dziuba J., Minkiewicz P., Mogut D.
Acta Scientiarum Polonorum. Technologia Alimentaria
|
2011
|
tom 10
|
nr 2
Background. Peptides are important components of foods mainly due to their biological activity. The basic method of their identification is reversed phase high-performance liquid chromatography coupled with electrospray-ionization mass spectrometry (RP-HPLC- -ESI-MS). Retention time (tR) prediction in silico is very helpful in analysis of multicomponent peptide mixtures. One of problems associated with RP-HPLC-ESI-MS is deterioration of mass spectra quality by trifluoroacetic acid (TFA). This problem can be avoided through the use of chromatographic columns designed for work with low TFA concentrations in mobile phase. The objective of this study was to determine the correlations between peptide retention times predicted with the use of a program available on-line and experimental retention times obtained using the column working with low TFA concentrations. Material and methods. The set of synthetic peptides and bovine α-lactalbumin fragments (18 peptides) was used in the experiment. Theoretical retention times were calculated using Sequence Specific Retention Calculator (SSRC) program. The experimental retention times were measured via RP-HPLC-ESI-MS method using column working with low TFA content. The dependence between theoretical and experimental tR was expressed via empirical equations. Results. The best correlation between theoretical and experimental retention times of peptides containing at least four amino acid residues has been obtained when third order polynomial (R2 = 0.9536). Prediction quality for diand tripeptides was significantly lower. The method described can be applied for cysteine-containing peptides although our sample preparation procedure did not include modification of this amino acid, taken into attention by SSRC program. Conclusions. The results of this study validate the usefulness of a third degree polynomial as a simple function describing the correlation between peptide retention times predicted by an on-line application and experimental retention times. The above function can effectively predict retention times in situations when experimental conditions differ from the computational environment (various columns, mobile phase composition, use or resignation from chemical modifications during sample preparation, various HPLC equipments). On-line available tR predicting application with correction based on user’s own data may be a useful tool in food peptidomics.
2

Exploration of anti-plasmodial activity of Prunus cerasoides Buch.-Ham. ex D. Don (family: Rosaceae) and its wood chromatographic fractions

86%
Sachdeva C., Kumar S., Kaushik N. K.
Acta Parasitologica
|
2021
|
tom 66
|
nr 1
3
Content available remote

Spectrophotometric methods as a novel screening approach for analysis of dihydropirimidine dehydrogenase activity before treatment with 5-fluorouracil chemotherapy

86%
Dolegowska B., Ostapowicz A., Stanczyk-Dunaj M., Blogowski W.
Journal of Physiology and Pharmacology
|
2012
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tom 63
|
nr 4
4

2D-TLC and RP-HPLC analysis of phenolic acids in some Carex species

86%
Bogucka-Kocka A., Krzaczek T.
Herba Polonica
|
2004
|
tom 50
|
nr 3-4
Phenolic acids from herbs of two genuses Carex were analysed by Thin-Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC). Ten following phenolic acids were identified: caffeic, protocatechuic, gentisic, p-coumaric, p-hydroxybenzoic, p-hydroxyphenylacetic, synapic, ferulic, syringic, and vanilic. These compounds were identified by comparison with authentic standards. By the RP-HPLC method the content of seven phenolic acids (caffeic, protocatechuic, p-coumaric, p-hydroxybenzoic, ferulic, syringic, and vanilic) was determined.
5

2D-TLC and RP-HPLC determination of phenolic acids in Passiflor and herb of Passiflora incarnata L.

86%
Smolarz H. D., Bogucka-Kocka A., Garbarczyk P. Z.
Herba Polonica
|
2004
|
tom 50
|
nr 3-4
The following phenolic acids: protocatechuic, p-hydroxybenzoic, o-hydroxybenzoic, cafFeic, syringic, p-coumaric and ferulic were detected in herb of Passiflora incarnata L. and in "Passiflor" by 2D TLC method. Derivatisation was performed with known reagents and two new ones containing solution of copper (II) and cobalt (II). The amount of seven phenolic acids were detected by RP HPLC method. The "Passiflor" specimen contains the same set and similar content of phenolic acids as herb of Passiflora incarnata L.
6

Column switching and liquid chromatographic technique for the rapid determination of fenoxycarb insecticide residues in apples

72%
Michel M., Krause A., Buszewski B.
Polish Journal of Environmental Studies
|
2001
|
tom 10
|
nr 4
Fenoxycarb residues are analyzed by column switching and reversed-phase high performance liquid chromatography (RP-HPLC). The active ingredient is extracted from apples on a silica gel column using a n-hexane - diethyl ether mixture. The eluate is evaporated, dry residue dissolved in acetonitrile-deionized water, and injected into the liquid chromatograph with a column switching system (C8 columns), and a UV-photodiode array detector (UV - PDA). The analyte is quantified by the external standard method. The average recoveries of the active ingredient from the spiked sample are 81.3 +/- 3.2% and 80.3 +/- 5.8%, the coefficients of variation are 3.9% and 7.2% for fortification levels 0.1 mg/kg and 0.05 mg/kg, respectively, and the limit of quantification at lambda = 228 nm is 0.05 mg/kg. Labor and organic solvent uses are greatly reduced in comparison to the existing methods. The overall procedure allows a sample throughput of up to 30 samples per day. The method was applied to the determination of fenoxycarb residue in apples from treated orchards.
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