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Open access

Ewelina Patyra, Ewelina Kowalczyk and Krzysztof Kwiatek

Abstract

A chromatographic procedure for determination of oxytetracycline (OXT), tetracycline (TC), chlorotetracycline (CTC), and doxycycline (DC) in water samples was developed and was applied for the analysis of water samples collected from poultry and pig farms and environmental water samples. Samples were acidified with trifluoroacetetic acid to pH 3 and further purified by solid phase extraction using Oasis HLB cartridges. The samples were dried up and redissolved in the mixture of oxalic acid and methanol. Separation was performed on reserved phase column (Phenomenex column C18 , 250 mm × 4.6 mm, 5 μm) by multistep gradient elution, and detection was carried out at 360 nm for OTC and TC, 370 nm for CTC, and 350 nm for DC. The tetracyclines were eluted with the mobile phase of 0.05 M oxalic acid (pH 2.5), acetonitrile, and methanol. This method provided average recoveries of 83.53% to 108.59%, with coefficient of variations (CVs) of 2.41% to 8.64% in the range of 10 to 1000 μg/L OTC, TC, CTC, and DC in water. The linearity for the tetracyclines was determined by HPLC-DAD in the range 10 to 1000 μg/L, with the correlation coefficient (R) > 0.99. The LOD and LOQ for the tetracyclines in water samples ranged from 1.51 to 4.00 and 2.51 to 5.93 μg/L, respectively.

Open access

Marzena Pawul-Gruba, Mirosław Michalski and Jacek Osek

Abstract

The high performance liquid chromatography with diode array detection was used for the study. The histamine was detected in 14.6% and 17.8% of the samples of fresh and smoked fish respectively. The highest concentrations of the compound were found in smoked herring and smoked sprat (17.7 mg/kg and 24.1 mg/kg respectively). Histamine concentration in fresh and smoked fish did not exceed the allowable limit, indicating that they are safe for consumers.

Open access

Katarína Hroboňová, Jana Sádecká and Jozef Čižmárik

Abstract

Dicoumarol is a mycotoxin, that acts as a blood anticoagulant, is formed during the microbial action of molds and fungi in spoiled hay or silage containing high-coumarin plant. A HPLC-DAD method for determination of coumarins, including dicoumarol, coumarin, and 4-hydroxycoumarin was developed. Methanol and acetic acid were used as mobile phase with gradient elution. The simultaneous separation was performed using C18 type of stationary phase. The recoveries were 88.6 – 92.6 %, 91.8 – 95.0 %, and 89.7 – 94.1 % (evaluated for three concentration levels) for dicoumarol, coumarin, and 4-hydroxycoumarin respectively. The parameters of system suitability (repeatability of retention times and peak areas) were determined for evaluation of the method. The method showed a good linearity in the concentration range 0.7 – 100 μg.mL−1 for dicoumarol, 0.05 – 100 μg.mL−1 for coumarin and 4-hydroxycoumarin with correlation coefficients higher than 0.9885. Extracts of sweet clover herb, hay, and spoiled hay were subjected to HPLC-DAD analysis. The most abundant compound in sweet clover herb and hay extracts was coumarin. In spoiled sweet clover hay extract the 4-hydroxycoumarin was detected in addition. The formation of 4-hydroxycoumarin was also observed in the synchronous fluorescence spectra recorded at the wavelength difference of 90 nm (difference between emission and excitation wavelength).

Open access

Agnieszka Kosińska, Anna Urbalewicz, Kamila Penkacik, Magdalena Karamać and Ryszard Amarowicz

SE-HPLC-DAD Analysis of Flaxseed Lignan Macromolecule and its Hydrolysates

A lignan macromolecule (LM) was extracted from defatted flaxseeds using an ethanol-dioxan system (1:1, v/v) and purified using Amberlite column chromatography with water and methanol as mobile phases. The LM was subjected to chemical hydrolysis (base, acid, base & acid), as well as to enzymatic processing using pepsin, pancreatin, cellulase, and β-glucuronidase.

The study revealed that lignan macromolecule in flaxseed was not homogenous. The chemical hydrolysis as well as enzymatic treatment using β-glucuronidase and cellulase released low molecular phenolic compounds from the lignan macromolecule. The liberation of secoisolariciresinol (SECO) and free phenolic acids (p-coumaric and ferulic acids) from flaxseed lignan macromolecule as a result of the base and acid hydrolyses was noted. The application of pepsin and pancreatin did not change the composition of the lignan macromolecule.

Open access

Bisera Janeska, Marina Stefova and Kalina Alipieva

Assay of flavonoid aglycones from the species of genus Sideritis (Lamiaceae) from Macedonia with HPLC-UV DAD

Flavonoids obtained from Sideritis species (Lamiaceae), S. raeseri and S. scardica, grown in Macedonia were studied. Qualitative and quantitative analyses of the flavonoid aglycones were performed using high-performance liquid chromatography (HPLC) with a UV diode array detector. Extracts were prepared by acid hydrolysis in acetone, re-extraction in ethyl acetate and evaporation to dryness; the residue dissolved in methanol was subjected to HPLC analysis.

Isoscutellarein, chryseriol and apigenin were identified in the extracts. Also, a 4'-methyl ether derivative of isoscutellarein was found, together with hypolaetin and its methyl ether derivative, which were identified according to previously isolated glycosides and literature data. Quantitation was performed using calibration with apigenin.

According to this screening analysis, the samples of the genus Sideritis from Macedonia are rich in polyhydroxy flavones and analogous with the previously studied Mediterranean Sideritis species from the Ibero-North African and Greek Sideritis species with respect to the presence of 8-OH flavones and their derivatives.

Open access

Anneli Salonen, Sanna Saarnio and Riitta Julkunen-Tiitto

Phenolic Compounds of Propolis from the Boreal Coniferous Zone

The profile of phenolic compounds in 19 propolis samples from different provinces in Finland were analysed for the first time using HPLC-DAD. Nine individual flavonoids (comprising 26% of the identified phenolics), eleven cinnamic acid derivatives (36%), two caffeic acid derivatives (14%), three chlorogenic acid derivatives (14%), and three other phenolic acids (10%) were found in the propolis samples. The compounds found in the largest quantities were methyl-naringenin and caffeic acid phenethyl ester (CAPE). The phenolic profiles of Finnish propolis show marked differences when compared with P. nigra and P. tremuloides propolis of Central European and Canadian origins. The phenolic compounds found in propolis samples are commonly found in the tree species growing in Finland. Non-metric multidimensional scaling showed that samples were scattered and they did not form clear groups according to the geographical origin or age of the sample.

Open access

R.V. Filimon, D. Beceanu, M. Niculaua2 and Cristina Arion

ABSTRACT -

The purpose of this study is to evaluate the anthocyanin (AC) and phenolic compounds (TPC) content, and the description of anthocyanin profile obtained by HPLC-DAD technique (High- Performance Liquid Chromatography - Diode Array Detector), from hydroalcoholic extracts of four varieties of sour cherry (Prunus cerasus L.) grown in experimental field of Research-Development Station for Fruit growing Iași, Miroslava area. Were also examined some physical-chemical properties of fruits, variety Mocăneşti 16 showing the highest moisture content (87.98%), titratable acidity (1.32 g malic/100g acid) and ascorbic acid (12 mg / 100g). AC, determined by pH differential method, had the highest value at Engleze timpurii variety (176.2 ± 0.97 mg/100g) and TPC, determined by the Folin-Ciocâlteu colorimetric method, had the maximum value at Mocăneşti 16 variety (446.89 ± 0.70 mg GAE/100g). Based on the chromatograms obtained, were identified four anthocyanins: cyanidin (cy)-3- glucoside, cy-3-rutinoside, cy-3- sophoroside, cy-3-glucosylrutinoside, expressed as a percentage of anthocyanins area. Anthocyanin profile obtained was not similar in varieties examined, and the ratio between anthocyanins differed from one variety to another. The data obtained confirm previous results on the sour cherries anthocyanin profile and can be used in food and pharmaceutical industry (functional foods) and as a basis of comparison for future studies.

Open access

Anna Madejska, Mirosław Michalski, Marzena Pawul-Gruba and Jacek Osek

Abstract

Introduction: In recent years, there has been a great interest in biogenic amines such histamine, as they are associated with the quality and safety of some kinds of fermented foods. The aim of this study was to evaluate the effect of temperature and storage time on the content of histamine in cheeses.

Material and Methods: Samples of mould and hard cheeses were examined with RP-HPLC with an organic-aqueous mobile phase containing acidic buffer and chaotropic salt. The samples were stored either at 22 ± 2°C for 42 days (mould and hard cheeses) or at 4 ± 2°C for 112 days (mould cheeses) and 133 days (hard cheeses).

Results: The mean total histamine content in cheeses stored at 22°C was higher than the content in those stored at 4°C, with the highest concentrations found in Gorgonzola Piccante cheese (730.47 mg/kg). Histamine concentration in some types of cheeses exceeded the toxic threshold dose, indicating that after long or inadequately cool storage they may not be safe for consumers.

Conclusion: To protect cheeses from contamination with histamine-producing bacteria and to safeguard consumers from poisoning, factors conducive to this amine’s formation should be minimised during cheese processing. Suitable temperature and time during storage of cheeses are recommended to avoid the intoxication. Monitoring of this toxin in food is necessary to ensure safety of consumers.

Open access

E. Patyra, E. Kowalczyk, A. Grelik, M. Przeniosło-Siwczyńska and K. Kwiatek

Abstract

A liquid chromatography – diode array detector (HPLC-DAD) procedure has been developed for the determination of oxytetracycline (OTC), tetracycline (TC), chlorotetracycline (CTC), doxycycline (DC), enrofloxacin (ENR), ciprofloxacin (CIP), sarafloxacin (SAR) and flumequine (FLU) residues in animal drinking water. This method was applied to animal drinking water. Solid-phase extraction (SPE) clean-up on an Oasis HLB cartridge allowed an extract suitable for liquid chromatographic analysis to be obtained. Chromatographic separation was carried out on a C18 analytical column, using gradient elution with 0.1% trifluoroacetic acid – acetonitrile – methanol at 30°C. The flow-rate was 0.7 mL/min and the eluate was analysed at 330 nm. The whole procedure was evaluated according to the requirements of the Commission Decision 2002/657/EC, determining specificity, decision limit (CCα), detection capacity (CCβ), limit of detection (LOD), limit of quantification (LOQ), precision and accuracy during validation of the method. The recoveries of TCs and FQs from spiked samples at the levels of 10, 100 and 1000 μg/L were higher than 82%. The developed method based on HPLC-DAD has been applied for the determination of four tetracyclines and four fluoroquinolones in animal drinking water samples.

Open access

Abdul Hameed and Naveed Akhtar

Abstract

In the present study, berries of two different species of Solanaceae family, Withania somnifera (WS) and Solanum nigrum (SN), were extracted in methanol and then fractionated with solvents, ranging from non-polar to polar, for their phytochemical profiling and investigation of antioxidant and tyrosinase enzyme inhibition capacity. The methanolic extract and n-hexane, ethyl acetate (WSEA, SNEA) and aqueous fractions were chemically analyzed and evaluated for biological activity. Total flavonoids and total phenolics were quantified in WSEA (96.91 ± 1.56 μg QE mg-1 sample and 178.45 ± 2.78 μg GAE mg-1 s ample, r esp.) and S NEA (89.58 ± 0.98 μg QE mg-1 sample and 120.15 ± 2.33 μg GAE mg-1 sample, resp.). HPLC-DAD analysis of ethyl acetate fractions of WS and SN measured 13.74 and 5.34 μg GAE mg-1 dry fraction and 3.72 and 3.41 μg QE mg-1 dry fraction, resp. WSEA and SNEA fractions showed the highest 2,2-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging, total antioxidant capacity and iron reducing power activity. The highest inhibition of tyrosinase enzyme was also exhibited by WSEA and SNEA (59.6 and 58.7 %) resp. This investigation justifies the medicinal value of W. somnifera and S. nigrum berry extracts as potential and readily available sources of natural antioxidants. Marked tyrosinase enzyme inhibition activity and antioxidant activity of both plant extracts might be due to polyphenols and flavonoids.