Gabriela Stanciu

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.

Trace element levels of three mushroom species

Abstract The aim of this study was to determine Cu, Fe and Cr contents of three species of fresh mushrooms and canned mushrooms: white and brown champignon (Agaricus bisporus) and Pleurotus Ostreatus. Were analyzed various plant parts: stem, cap and cuticle of fresh mushrooms and only stem and cap for canned mushrooms. The levels of trace metals of mushroom samples collected from regions of Romania, Poland and Turkey were determined by UV/Visible spectrometry - standard addition method after digestion method. The contents of investigated trace metals in mushroom samples were found to be in the range of 0.01 - 2.26 mg/Kg for chromium, 2.02 - 430.67 mg/Kg for copper and 240.40 - 7952.89 mg/Kg for iron. The iron content was found to be higher than those of the other two minerals in all the samples. Mushrooms species in the highest levels of trace elements were found white champignon for Cu and Fe and brown champignon for Cr.

Determination of organophosphorus pesticides in baby food

Abstract Measurements of organophosphorus pesticides residues were conducted on four different baby food puree based on vegetable, fruit, white fish and veal, products based on cereals and biscuits packed in cardboard box using gas chromatography with thermoionic specified detector (GC-TSD). The lowest concentration of organophosphorus compounds was found for sulfotep, 0.00006 mg/kg in biscuits, while the highest concentrations were found for diazinon and fenchlorphos, with values of 0.1096 mg/kg and 0.1903 mg/kg, both in the grain samples.

Heavy Metals and Pesticides Analysis from Black Sea Algae

Our studies were focused on heavy metals (Cd, Cu, Zn, and Pb) and pesticides analysis from two different types of marine algae in order to assess their capabilities to be used as raw material for pharmaceutical purposes without risks for human health. The analysed algae, Cystoseira barbata and Ceramium rubrum, have been collected from Romanian Black Sea Coast in the southern zone Tuzla — Vama Veche where the biomass has increased in 2007. The used analytical techniques were atomic absorption spectrometry (AAS) for heavy metals and gas chromatography with electron capture detector (GC-ECD) and thermoionic specific detector (GC-TSD) for organochlorine respectively organo-phosphoric pesticides. The results indicate that heavy metals and pesticides levels are very low, similar with other reported data. The bioaccumulation abilities for studied contaminants are higher for Ceramium rubrum than for Cystoseira barbata.

Quantification of sugar in different brands of drinks

Abstract The levels of invert sugar (glucose/fructose mixture resulting from inversion) were determined in different brands of orange, grapefruit, lemon, apricot and raspberry products. Samples of fresh juice, soft drink, syrup, nectar and compote were representative of the Romanian market. The invert sugar was quantified by Ofner’s method (a titrimetric method) and the refractive and Brix indices were measured for the quantification of sucrose in studied samples. International Commission for Uniform Methods of Sugar Analysis accepts reading of sugar content based on the refractive properties of sucrose despite the fact that the sugar in analyzed juice sample is fructose, not sucrose. This usually does not result in significant error. There were significant differences among orange, grapefruit, lemon, apricot and raspberry products brands, in the levels of sugars.

Nitrite determination in spices

Abstract The aim of this study is to determine the nitrite content in some spices: basil, pepper, dill, thyme, oregano, bay leaves, cinnamon, mint, mustard and cumin. The nitrite content was measured using UV-VIS spectrometric method with Griess reagent. The method was tested and partial validated. The nitrite content varied from 0.23 to 7.7 mg/Kg and these values are lower than those encountered in the literature.

Characterization and stability study of some pharmaceutical ointments

Abstract In the present study we have determined some characteristics (aspect, odor, solubility, emulsion type, water and volatile substances content, total fatty matter, saponification index, ester index) for three pharmaceutical ointments belonging to the group of non-steroidal anti-inflammatory: Diclac, Ketonal, Indometacin and one antibiotic ointment for ophthalmic use: Ophtagram. In order to achieve stability study of studied ointments, the pH, the acidity index, the peroxide index and the iodine index were determined over a year every three months. After 9 months from the opening of the tubes, analytical determinations have shown that pH values, acidity, peroxide and iodine indexes no longer fit to the values recommended for medical use, which confirms the directions available on the package.