Nicoleta Matei

Rapid HPLC method for the determination of ascorbic acid in grape samples

A simple, fast and sensitive high-performance liquid chromatography/electrospray ionization-mass spectrometry method is described and validated in terms of linearity, accuracy/recovery and reproducibility, as well as limit of detection for the determination of ascorbic acid from grape (Vitis vinifera L.) samples from Murfatlar vineyard. Good linearity (correlation factor > 0.9970) was achieved in the concentration range 0.5–15 μg mL−1 for AA in acetic acid 0.1% solution. The obtained RSD values (below 5%) indicated excellent repeatability of the proposed method. The limit of detection was 0.32 μg mL−1 while the recovery ranged between 96.86 and 102.41%. The advantages of the method are: small amounts of sample and solvents, short analysis time and minimum steps for sample preparation.

Cadmium and lead occurrence in soil and grape from Murfatlar Vineyard

Abstract The study investigates the pollution with heavy metals of grapes and soil. The grapes nourish from the respective soil, with all existing substances: either nutrients or toxic materials. This link, between grapes and soil, made mandatory to focus on observing the level of toxic materials in both samples grapes and land. The aim of this research is to analyze the level of Cd and Pb in Vitis vinifera L. grape fruits and soil, by flame atomic absorption spectrometry (FAAS) method. The grapes and the soil used in this work were sampled from the Murfatlar City, a nonindustrial area, placed far from the car traffic pollution. Cd and Pb were quantified, after the chemical mineralization of the samples using nitric acid. It can be noticed that the values of cadmium and lead concentrations in grapes were lower than the recommendable maximum limit.

Spectrophotometric determination of ascorbic acid in grapes with the Prussian Blue reaction

Abstract The objective of the present work was to adapt the Prussian Blue reaction for the determination of ascorbic acid. The procedure was successfully applied for the determination of ascorbic acid in red and white grapes (Vitis vinifera L.) just previous ingathering. In the present work was used the red and white grapes from Murfatlar vineyard: Mamaia, Cabernet Sauvignon, Merlot, Pinot Noir, Chardonnay, Sauvignon, Muscat Ottonel and Riesling Italian. The results were situated in the range of 0.67 - 1.79 mg vitamin C/100g product for red grapes and respectively 0.50 - 1.49 mg vitamin C/100g for white grapes.

Determination of loratadine in pharmaceuticals by a spectrophotometric method

Abstract The spectrophotometric method for determination of loratadine using tetraiodomercurate has been applied in various pharmaceutical formulations. The results confirmed that recovery value is optimum and the method is valid, thus it can be used in quality control and evaluation of loratadine tablets, oral formulations of mixed composition, oral solutions, etc. The method is easy and simple to apply, does not require complicated equipment and spectrophotometric reading time is reduced, which allows a large number of analyzes in a relatively short time.

Applications of a DAD-HPLC method for determination of loratadine on biological samples

Abstract The aim of research is to assess the active substance by a HPLC method for the separation and quantitative determination of loratadine. The method has been developed and validated on the standard solutions, in previous research. The current study was undertaken to present the results obtained from loratadine determination in biological samples (human serum, urine and breast milk). These results may be applicable on patients with different physiological conditions (aging, pregnancy or recently giving birth, etc.) and pathological conditions which may interfere with the metabolism of loratadine. The used HPLC method detected loratadine concentrations in human serum samples, respectively urine samples, at 2 hours after drug administration. The method detected traces of loratadine which passed into breast milk, as well. Data were statistically interpreted using MED CALC 10.2 software. These results show that the applied method can be used for quantitative analysis of loratadine in biological fluids (all permissible limits of quality specifications being in the range 95- 105%).

Determination of caftaric acid in tincture and rose water obtained from Rosae damascenae flores

Abstract Polyphenolic compounds were determined from a pharmaceutical (tincture) and a cosmetic preparation (rose water), both obtained from the Rosae damascenae flores. Separation of the phenolic compounds was done by a HPLC method, using a Zorbax XDB or equivalent column C18, 250 mm x 4,6 mm; 5 μm. A gradient elution was performed with phosphoric acid and acetonitrile eluted under gradient conditions. The flow rate was 1.5 mL/min and the injection volume was 20 μL. HPLC method for determination of caftaric acid presented in this paper, has been validated. The results were statistically analyzed with SPSS 10 software.

Simultaneous quantification of four benzodiazepines from whole blood by highperformance liquid chromatography in forensic toxicological analysis

Abstract A rapid high performance liquid chromatography method, using a monolithic column, was developed for quantitative determinations of benzodiazepines (diazepam, clonazepam, lorazepam, midazolam) in whole blood. A liquid-liquid extraction step with n-chlorobutane isolates the drugs from alkalinized blood. The separation was carried out in reversed phase conditions using a Chromolith Performance (RP-18 100x4.6 mm) column. For the mobile phase, a mixture of a phosphate buffer (pH= 2.5)/acetonitrile (65/35 v/v), in isocratic mode at 2 mL/min. An ultraviolet spectrophotometer was used as the detector at the wavelength of 220 nm. The total run time of the analytical method is less than 4-6 minutes. The calibration curves showed linearity and the correlation coefficient of each individual curve was greater than 0.995. The method was linear over a concentration range of 0.03-0.6 μg/mL for clonazepam, lorazepam and midazolam. For diazepam of linearity was over the range 0.04-5.0μg/mL. Quantification limits ranged from 0.03-0.04μg/mL and the accuracy were from 80% to 105% for the recovery test. The results indicate that this analytical method is simple, specific, accuracy, sensitive, demonstrating from the validation data and a higher robustness. The proposed method is applied routinely in forensic toxicological analysis involving blood.

CONTENT OF ORGANIC POLLUTANTS (PAHS AND POPS) IN SURFACE WATERS FROM DANUBE DELTA AND PLITVICE LAKES

The objective of this work was to assess the contents of selected organic pollutants (polycyclic aromatic hydrocarbons PAHs and organochlorine pesticides POPs) in the surface waters of Danube Delta and Plitvice Lakes. These organic pollutants are among the most prevalent pollutants, being detected in almost all environmental compartments. The analyses of PAHs were performed by gas chromatography with mass spectrometer detector (GC-MS) and that of POPs by gas chromatography with electron capture detection (GC-ECD).

Determination of heavy metals and c vitamin in allium plants (garlic and onion)

Analyses of plants render important information in toxicological and environmental investigations since plants are a very significant link in the trophic chain. The aim of this study was to analyze quantitatively the distribution of heavy metals and ascorbic acid in Allium plants: Allium sativum L. (garlic) and Allium cepa L. (onion). Heavy metals accumulation in garlic and onion was quantified by flame atomic absorption spectrometry (FAAS) after the chemical mineralization of the samples with nitric acid and hydrogen peroxide in a Digesthal device. To determinate of vitamin C we used a titrimetric method with potassium brommat-bromide solution in acid medium, when vitamin C is oxidized to dehidroascorbic acid by bromine. Our results indicate a high concentration of vitamin C in leaves of the studied Allium plants.