Simona Dobrinas

Spectrometric studies about some dyes — anionic surfactant interactions in aqueous solutions

This work presents some alternative analytical methods for anionic surfactant quantitative determination in aqueous solutions. Interactions of aqueous solutions of three dyes (Rhodamin B, Methyl violet and Fuchsin basic), concentrations 0.3x10(-6) M, with two anionic surfactants in the concentration range of 10(-5) M (sodium salt of naphthalene sulphonate formaldehyde condensates and melamine sulphonate formaldehyde condensates) have been investigated. Spectrometric measurements were performed on an UV-Vis spectrometer Hewlett Packard 8452A with diode array detection. From the UV-Vis spectra of individual and mixed dye-anionic surfactant aqueous solutions in various concentration ranges, specific changes in the chromophore microenvironment and in the intensity of absorbance is observed. These changes can be attributed to the chemical and structural characteristics of dyes and anionic surfactants, and could be exploited for analytical purposes.

Polycyclic aromatic hydrocarbons and pesticides in milk powder.

This Research Communication reports analysis of 37 compounds comprising polycyclic aromatic hydrocarbons (PAHs), organochlorine and organophosphate pesticides (OCPS and OPPS) in milk powder (one brand each of commercial infant formulae, follow-on formulae and baby formulae purchased from a local supermarket in Romania). The selected analytes were investigated using gas chromatography-mass spectrometry (GC-MS), gas chromatography with electron capture detector (GC-ECD) and gas chromatography with thermionic sensitive detection (GC-TSD). The estimated limits of detection for most target analytes were in the μg/kg level (range 0·001-0·320 µg/kg). The purpose of the study was to determine the selected analytes, to assess the exposure of babies and infants and to produce data for comparison with tolerable limits according to the European Union Regulations. In most of the samples the organochlorine pesticides values were under the limit of detection. Exceptions were heptachlor epoxide and endosulfan sulphate, the last of which was found in all analysed samples at low concentrations. We also found detectable levels of ethoprophos, parathion-methyl, chlorpyrifos, prothiofos, guthion, disulfoton and fenchlorphos in most of the analysed samples. Benzo[a]pyrene, which is used as an indicator for the presence of PAHs, was not detected in selected samples. The low level of exposure to contaminants indicates that there are no health risks for the infants and babies that consume this brand of milk powder formulae.

THREATS ON THE SEASIDE LAKES WATER AND THEIR ACUTE AND LONG-TERM CONSEQUENCES

Black Sea’s pollution by organic and inorganic pollutants occurs frequently due to the fact that in the sea water there are discharged some waste waters (industrial or home originated) and surface waters with a high pollutants concentration. The conservation of surface waters quality in order to prevent and control the Black Sea coast pollution constitutes a problem of national, even international interest. In this purpose data were collected between 1995 – 2004 regarding the Corbu, Tasaul, Siutghiol, Tabacarie, Hagieni, Limanu lakes. From time to time, the Nuntasi, Agigea, Tatlageac, Neptun, Golovita, Zmeica, Razim, Sinoie, and Belona Lakes were also investigated. This lakes are located in the central and southern part of Romanian Black Sea coast and represent ecosystems contaminated by the anthropic influences. Mean values of inorganic constituents (including nutrients, metals etc.) and global organic pollution in correlation with measured biological parameters (primary production) are reported.

Polycyclic Aromatic Hydrocarbons in Romanian Baby Foods and Fruits

Levels of polycyclic aromatic hydrocarbons (PAHs) in commercially available baby food and in different sorts of fruits were investigated. PAHs determination was performed by gas chromatography coupled with mass spectrometry (GC/MS). The sum of 15 PAHs varied in baby food from 2.52–6.7 μg/kg and in fruits from 0.40–21.52 μg/kg. Benzo[a]pyrene used as a marker for PAHs contamination was detected in lower levels in baby food than the maximum tolerable limit (1 μg/kg) stated in Commission Regulation no 1881/2006.

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.

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 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.

Pesticide Residues Determination in Vegetables from Romania by GC-ECD

Pesticide use raises a number of environmental concerns. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including non-target species, air, water, bottom sediments and food. Pesticide drift occurs when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them. In this study the organochlorine pesticides have been measured in vegetables samples from Dobrogea county, Romania, by gas chromatography with electron capture detector (GC-ECD) after extraction and clean-up step and also the calculated bioconcentration factor (BCFs values) were used to relate pesticide residues in plants to the pollutant concentration in soils. The pesticides concentrations were at ppb levels and BCFs values were below 1.

DETERMINATION OF ORGANOCHLORINE AND POLYCYCLIC AROMATIC HYDROCARBONS PESTICIDES IN HONEY FROM DIFFERENT REGIONS IN ROMANIA

In this study honey collected from local markets or made by private peasants from eighteen regions of Romania during years 2002-2004 were analyzed for organochlorine pesticides (OCPs). An analytical procedure based on liquid-liquid extraction with n-hexane followed by gas chromatography with electron capture detection (GC-ECD) has been developed. For clean-up and preconcentration purposes was used a usual sorbent material (florisil). Limits of detection were from 0.02 and 0.05 μg /Kg. The pesticide endrin was the most frequently detected in 61% of the samples, followed by dieldrin in 16% of the samples. DDT and their metabolites were detected in 11% of the samples. Results indicate that honey consumers should not be concerned about the amounts of organic pollutants found in Romanian honey.