Belgin Izgi

Photocatalytic degradation of Congo Red by hydrothermally synthesized nanocrystalline TiO2 and identification of degradation products by LC-MS.

Degradation of Congo Red (CR) dye in aqueous solutions was investigated by means of photocatalysis of TiO2 which was hydrothermally synthesized at 200 degrees C in 2 h, in anatase phase with 8 nm crystallite size. Efficiency of TiO2 in photocatalytic degradation under visible irradiation was studied by investigating the effects of amount of TiO2, irradiation time, initial CR concentration and pH. It was found that complete decolorization is achieved within 30 min of irradiation. Effects of nitrate and sulphate ions and humic acid on the degradation were also tested. The results were compared with Degussa P-25 TiO2 at the same degradation conditions. Degradation products were detected using LC-MS technique. The probable pathways for the formation of degradation products were proposed.

Fractionation and speciation of Cu, Zn and Fe in wine samples by atomic absorption spectrometry

Abstract A scheme is presented for fractionation of wine components and Fe, Cu and Zn determination in different fractions. The charge of the metal species was established using cation and anion exchange separation based on solid phase extraction. The resin XAD-8 was used for the separation of wine polyphenols in complexes with wine proteins and polysaccharides. Dowex ion exchange resins were used for the separation of cationic and anionic species of Fe, Cu and Zn. Flame atomic absorption spectrometry and electrothermal atomic absorption spectrometry were used off-line for the quantitative determination of metals in the different fractions obtained.

Application of factorial design for mercury determination by trapping and graphite furnace atomic absorption spectrometry

Abstract A trapping technique was developed for the determination of mercury traces in blood serum by graphite furnace atomic absorption spectrometry (GFAAS). The mercury was converted to metallic vapour in a reaction cell by tin chloride solution, swept by nitrogen into a gold-plated graphite tube and subsequently atomized. The influence of four experimental factors on the sensitivity of mercury determination was examined using two level factorial designs. It was found that the solution volume is the most significant parameter.

Direct atomic absorption spectrometry determination of tin, lead, cadmium and zinc in high-purity graphite with flame furnace atomizer☆

This work described methodology of Sn, Pb, Cd and Zn impurities determination in high-purity graphite at direct atomic absorption spectrometry (AAS) with flame furnace (FF) atomizer. It was evidence that quality of AAS measurements are depended from sample amount, its homogeneity, particle size, as well as calibration procedure and operation parameters of FF atomizer. Prior to analysis the method has been developed and optimized with respect to the furnace heating temperature and flame composition of FF atomizer. Conditions of absorption peak areas (Q(A)) formation to each element were studied on the basis of contribution into its value some of individual parameters of analytes, including mass-transporting process from increasing mass of graphite samples into gas phase. Because particle size and homogeneous distribution of analyte in powdered materials has an enormous influence on accuracy and precision of measurement results, graphite as well as appropriate series of powdered reference standards was previously ground and investigated. Graphite samples to be analyzed and standard reference materials with mass from 0.025 to 0.200g was previously briquetted as pellet and insert on corresponding hole in furnace. The characteristic mass (g(0)) of Sn, Pb, Cd and Zn were 0.35, 0.1, 0.008 and 0.025ng, respectively, and relative standard deviation (S(r)) not more than 20%.

Blood lead levels of traffic policemen in Bursa, Turkey

This study was conducted in January 2001, in Bursa, Turkey. Of the 99 traffic policemen who were included in the study, 21 were office workers. Blood lead levels were determined by using an electro-thermal atomic absorption spectrometer (ET-AAS). Average blood lead levels were 9.4 +/- 1.6 micrograms/l and 8.7 +/- 1.7 micrograms/l for policemen working outdoors and indoors, respectively. The difference between the two groups was statistically insignificant (P > 0.05). When policemen less than 15 years on duty were taken into account (n = 48) the difference between the outdoors and indoors working groups was significant (9.3 +/- 1.3 and 8.2 +/- 1.8 micrograms/l, P < 0.05). In order to prevent the negative effects of tetraethyl lead on humans and the environment the use of lead in petrol must be prohibited.

Element Content (Cu, Fe, Mn, Ni, Pb, and Zn) of the Ruderal Plant Verbascum olympicum Boiss. from East Mediterranean

In this study, heavy metal content (Cu, Fe, Mn, Ni, Pb, Zn) was determined in soils and different organs of Verbascum olympicum Boiss. This species is endemic to Uludağ and spreads on destroyed areas such as: roadsides, developed building areas, ski lift stations and sheep folds. Soils and different organs (roots, stems, leaves and flowers) of plant samples were analyzed using an atomic absorption spectrophotometer for determining the element content. Heavy metal contents in soils and different organs in this species were highly correlated (P < 0.05). However, the contribution of plant organs to the accumulation capacity varied according to the metal. These results suggest that this species may be useful as a bioindicator for heavy metals.

Determination of bromine and tin compounds in plastics using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).

The polybrominated flame retardants and organotin compounds were screened in terms of bromine and tin content using laser ablation inductively coupled plasma mass spectrometry in plastics. The calibration standards were prepared using the fused-disk technique, and all samples were investigated under optimal conditions. Using a central composite experimental design, laser parameters, laser energy, pulse rate, scan rate and spot size were identified. The detection limits of the method were 1000 mgkg(-1) and 1600 mgkg(-1) for bromide and tin, whereas the relative standard deviation (%) values of the analysis were 9% and 6% (n=3) for ERM EC681k with 770 ± 70 mgkg(-1) Br and 86 ± 6 mgkg(-1) Sn respectively, and 106-115% of Br and 102-104% of Sn were observed for the tetrabromobisphenol A and butyltin trichloride spike plastics, respectively.

An alternative method for screening of Sudan dyes in red paprika paste by gas chromatography-mass spectrometry

An indirect analytical screening method for Sudan dyes by gas chromatography mass spectrometry was developed as an alternative method to novel liquid chromatography mass spectrometry. Red paprika paste samples were extracted with acetone and centrifuged at room temperature. The supernatant was removed from the solution and buffered. The reduction step is performed chemically with sodium dithionite and corresponding dyes as amine products were identified by GC-MS. The method was validated for analytical properties using spiked paste samples. Several parameters which may influence the reduction procedure, such as temperature and the amount of reducing agent, were optimized using central composite design methodologies for Sudan III in order to increase its lower apparent recovery as compared with the others. Optimum conditions for Sudan III were found to be 45 °C and 1.3 M by using a central composite design. The apparent recovery values were 77.6%, 69.4%, 51.3%, 42.5% with relative standard deviations of 31.8%, 20.4%, 20.3%, 31.2% for Sudan I, II, III, IV dyes respectively. This method was used successfully for screening of Sudan dyes in paprika paste products by GC-MS.

Lead Fractionation Analysis in Lipstick Samples by Inductively Coupled Plasma-Mass Spectrometry

A new analytical approach based on fractionation was introduced for lead in lipstick samples. Different separation techniques including n-hexane, glycerol extraction, and activated carbon adsorption were used to characterize the lipid fraction, polar and aromatic components of the samples. Additionally, artificial saliva and food stimulant extractions were used for the risk assessment studies. Trace metal levels in fractions were determined by inductively coupled plasma-mass spectrometry. Method validation parameters in the total element determinations were defined in terms of detection limits, accuracy, and precision. The limits of detection and quantification were 0.02 and 0.07 mg kg−1 for Pb; whereas the repeatability and reproducibility of the results based on percent relative standard deviation were 3.0% and 7.2% for lead, respectively.