Trace-metal distribution of cigarette ashes as marker of tobacco brands.

The trace-metal distribution of cigarette ashes offers a potential interest from the point of view of forensics and criminology dealing with the determination and classification of tobacco brands. There is a vast bibliography related to the determination of different metals in tobacco leaves. Nevertheless, none of them are directly linked to this matter. Therefore, in this work we present a methodology to assess the viability of discriminating between different tobacco brands by analysing the ashes after smoking. This methodology encompasses the data analysis by atomic techniques (inductively coupled plasma) and further data analysis by principal component analysis and partial least squares-discriminant analysis. The metal distribution (Zn, B, Mn, Fe, Mg, Cu, Ti, Al, Sr, Ca, Ba, Na, Li, and K) of cigarette ashes of different tobacco brands was determined in 149 samples obtained from local stores, representing the most common brands of cigarettes readily available to consumers in Spain. Further analysis of the data with PCA denoted significant differences between different brands of tobacco in their metallic content. In that sense, blond tobaccos were found to contain different patterns in metallic content than black tobaccos. Intrinsic differences were found between different brands, being possible to study the relationship between each brand and its metallic concentration and compare this relationship with other brands. Moreover the possibility of developing classification models to be able to discriminate between different brands was also introduced.

Application of enzymatic probe sonication extraction for the determination of selected veterinary antibiotics and their main metabolites in fish and mussel samples.

A new method based on enzymatic probe sonication extraction prior to high-performance liquid chromatography (HPLC) has been developed for the determination of 11 antibiotics (drugs) and the main metabolites of five of them in fish tissue and mussel samples. The analytes belong to four different classes of antibiotics (sulfonamides, tetracyclines, penicillins and amphenicols). The analysed compounds were sulfadiazine (SDI) and N(4)-acetylsulfadiazine (NDI) metabolite, sulfamethazine (SMZ) and N(4)-acetylsulfamethazine (NMZ), sulfamerazine (SMR) and N(4)-acetylsulfamerazine (NMR), sulfamethoxazole (SMX), trimetroprim (TMP), amoxicillin (AMX) and its main metabolite amoxicilloic acid (AMA), ampicillin (AMP) and its main metabolite ampicilloic acid (APA), chloramphenicol (CLF), thiamphenicol (TIF), oxytetracycline (OXT) and chlortetracycline (CLT). The main factors affecting the extraction efficiency (type of enzyme, type and volume of extractant, ultrasounds power and extraction time) were optimised in tissue of hake (Merluccius merluccius), anchovy (Engraulis encrasicolus), mussel (Mytilus sp.) and wedge sole (Solea solea). The extraction was carried out using an extraction time of 5 min with 5 mL of water and subsequent clean-up with dichloromethane. High-performance liquid chromatography (HPLC) with diode array (DAD) and fluorescence (FLD) detectors was used for the determination of the antibiotics. The separation of the analysed compounds was conducted by means of a Phenomenex Gemini C(18) (150 mm x 4.6 mm I.D., particle size 5 microm) analytical column with LiChroCART LiChrospher C(18) (4 mm x 4 mm, particle size 5 microm) guard-column. Analysed drugs were determined using formic acid 0.1% (v/v) in water and acetonitrile in gradient elution mode as mobile phase. The proposed method was also evaluated by a laboratory assay consisting of the determination of the targeted analytes in samples of Cyprinus carpio which had previously administered the antibiotics.