Raluca Popescu

Geographical and Botanical Origin Discrimination of Romanian Honey Using Complex Stable Isotope Data and Chemometrics

Our research is of particular interest in the geographical discrimination of honey from different floral sources and different regions of Romania as support for quality assessment and classification activities, to establish potential origin markers. In this study, stable isotopes selected as representative discrimination parameters of different botanical or geographical origin were determined in 40 honey samples using isotope ratio mass spectrometry (IRMS) and site-specific natural isotopic fractionation measured by nuclear magnetic resonance (SNIF-NMR) methods. Data on δ13C, δ18O, and δ2H of honey measured by IRMS together with the stable isotopes (δ13C and D/H) in ethanol from fermented honeys were reported, and it was demonstrated that the use of δ13C value as single parameter in distinguishing honey floral variety is not practicable. Therefore, a particular emphasis was put on the (D/H)I from ethanol which is specific to a given botanical origin of honey, and its potential in characterizing the substances was highlighted both for assignment of origin and combat of adulteration.

Classification of red wines using suitable markers coupled with multivariate statistic analysis

Methodologies for chemometric classification of five authentic red wine varieties from Murfatlar wine center, Romania, young and aged are reported. The discriminant analysis based on several anthocyanins, organic acids, (13)C/(12)C, (18)O/(16)O and D/H isotopic ratios, (1)H and (13)C NMR fingerprints revealed a very satisfactory categorization of the wines, both in terms of variety and vintage, thus illustrating the validity of selected variables for wine authentication purposes. LDA applied to the combined data shows 85.7% classification of wines according to grape variety and 71.1% classification of wines according to vintage year, including a control wine set for each categorization, thus allowing an accurate interpretation of the data. Thereby, anthocyanins, certain anthocyanin ratios, oxalic, shikimic, lactic, citric and succinic acids, sugars like glucose, amino acids like histidine, leucine, isoleucine and alanine, and also 2,3-butanediol, methanol, glycerol and isotopic variables were significant for classification of wines.

Using stable isotopes in tracing contaminant sources in an industrial area: A case study on the hydrological basin of the Olt River, Romania.

Tracing pollution sources and transformation of nitrogen compounds in surface- and groundwater is an issue of great significance worldwide due to the increased human activity, translated in high demand of water resources and pollution. In this work, the hydrological basin of an important chemical industrial platform in Romania (Ramnicu Valcea industrial area) was characterized in terms of the physico-chemical and isotope composition of δ(18)O and δ(2)H in water samples and δ(15)N of the inorganic nitrogen species. Throughout a period of one year, water samples from the Olt River and its more important tributaries were collected monthly in the industrial area, when the seasonal and spatial isotope patterns of the surface waters and the main sources of pollution were determined. Higher inorganic nitrogen concentrations (up to 10.2 mg N L(-1)) were measured between November 2012 and April 2013, which were designated as anthropogenic additions using the mixing calculations. The main sources of pollution with inorganic nitrogen were agriculture and residential release. The inorganic nitrogen from the industrial waste water duct had a distinct δ(15)N fingerprint (mean of -8.6‰). Also, one industrial release into the environment was identified for Olt River, at Ionesti site, in November 2012. The mean precipitation samples had the lowest inorganic nitrogen concentrations (less than 5.5 mg N L(-1)) with a distinct δ(15)N fingerprint compared to the surface and industrial waters.

Characterization of the Quality and Floral Origin of Romanian Honey

ABSTRACT Characterization of acacia, sunflower, rape, linden, and polyfloral Romanian honey was performed by high performance liquid chromatography, nuclear magnetic resonance (NMR), and physicochemical analysis for classification by floral origin and to assess quality and storage conditions. The pH, electrical conductivity, moisture content, total solids, fructose/glucose ratio, 1H and 13C NMR spectra, and 5-(hydroximethyl)-2-furaldehyde were measured in reference samples and in commercial honey of unknown floral origin. Polyfloral, sunflower, and linden varieties showed high electrical conductivity values between 400 and 550 µS/cm, whereas acacia and polyfloral honeys had high fructose/glucose ratios and total solids. Commercial samples of unknown floral origin were of lower quality, as half contained 5-(hydroximethyl)-2-furaldehyde concentrations between 15 and 130 mg/kg. Chemometric assessment of the results provided good discrimination between acacia, rape, and polyfloral honeys, whereas linden and sunflower varieties partially overlapped. The most significant parameters of discrimination were electrical conductivity, total solids, the 1H NMR peak at 5.44 ppm, and the 13C NMR peak at 69.65 ppm.

Isotopic fingerprint of the middle Olt River basin, Romania

One of the most important tributaries of the Danube River in Romania, the Olt River, was characterized in its middle catchment in terms of the isotopic composition using continuous flow–isotope ratio mass spectrometry (CF–IRMS). Throughout a period of 10 months, from November 2010 to August 2011, water samples from the Olt River and its more important tributaries were collected in order to investigate the seasonal and spatial isotope patterns of the basin waters. The results revealed a significant difference between the Olt River and its tributaries, by the fact that the Olt River waters show smaller seasonal variations in the stable isotopic composition and are more depleted in 18O and 2H. The waters present an overall enrichment in heavy isotopes during the warm seasons.