Validation of a GC-IDMS method for the metrologically traceable quantification of selected FAMEs in biodiesel

Current methods for the analysis of fatty acid methyl esters (FAMEs) in rapeseed oil based biodiesel refer to operationally defined measurands, which is a practical solution for routine analysis. In this paper, a new method for the SI-traceable quantification of selected FAMEs in biodiesel and its validation are described. This method has the potential to be a reference method for applications requiring structurally defined measurands and traceability to the SI as it allows direct comparisons to well characterised calibrants through the use of isotopically labelled analogues of the analytes as well as establishing of a full uncertainty budget. The method is based on gas chromatography-isotope dilution mass spectrometry. Its performance is demonstrated through its implementation and validation in two independent laboratories and is shown to provide reliable and traceable results for selected FAMEs in biodiesel test samples.JRC.D.2-Standards for Innovation and sustainable Developmen

Synthesis of organic and polymeric 3-hydroxyflavone based fluorescent sensors

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2013Bu çalışmada, Suzuki kenetlenme reaksiyonu kullanılarak, 3-hidroksiflavonların fluoren, karbazol ve tiyofenlerle polimerleri elde edilmiş ve özellikleri incelenmiştir. 3-Hidroksiflavonların hidroksil grupları metoksimetil (MOM, CH3OCH2OCH2-) ile korunduktan sonra polimerleşme reaksiyonları gerçekleştirilmiş ve daha sonra koruma grubu kaldırılarak ürünlerin özellikleri incelenmiştir. Farklı çözücüler içerisinde floresans ölçümleri yapılmış, kuantum verimleri hesaplanmıştır. Buna ek olarak kullanılan 3-hidroksiflavonların eldesi için mevcut sentez yöntemlerinin bazı modifikasyonlar ile yeni bir yöntem geliştirilmiştir. Bu yöntemle B halkasının para konumunda bir hidroksil grubu içeren flavon da dahil olmak üzere bir seri 3-hidroksiflavon sentezlenmiştir. Literatürdeki çalışmalarla karşılaştırıldığında, yeni yöntemle flavonlar daha yüksek verim ve daha kısa reaksiyon süreleri ile tek basamakta elde edilmiştir. Ara ürün (çalkon) izole edilmeden gerçekleştirilen reaksiyonda yan ürün (auron) oluşmadığından ilave bir saflaştırma işlemine gerek duyulmamıştır.In this study, a series of 3-hydroxyflavone (3HF) based copolymers with fluorene, carbazole and thiophene were synthesized by Suzuki coupling polymerization. The hydroxyl functionalities of the 3-hydroxyflavones were protected with methoxymethyl (MOM, CH3OCH2OCH2-) group and then the coupling reactions were performed. The optical properties of the MOM protected and deprotected copolymers in different solvents were investigated and the quantum yields were calculated. Modification of the present synthetic methods led to the syntheses of 3-hydroxyflavones in a shorter reaction time, with simple purification and in higher yields. Application of the method provided the syntheses of 3HFs having a hydroxyl group on the phenyl ring (ring B) in one step, which is an important improvement compared to the current method available in the literature. It involves four steps, longer reaction time and gives lower yield.Ph.D.Doktor

CCQM-K131 Low-polarity analytes in a multicomponent organic solution: polycyclic aromatic hydrocarbons (PAHs) in acetonitrile

Solutions of organic analytes of known mass fraction are typically used to calibrate the measurement processes used to determine these compounds in matrix samples. Appropriate value assignments and uncertainty calculations for calibration solutions are critical for accurate measurements. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2015 the Organic Analysis Working Group (OAWG) sponsored CCQM-K131 "Low-Polarity Analytes in a Multicomponent Organic Solution: Polycyclic Aromatic Hydrocarbons (PAHs) in Acetonitrile". Polycyclic aromatic hydrocarbons (PAHs) result from combustion sources and are ubiquitous in environmental samples. The PAH congeners, benz[a]anthracene (BaA), benzo[a]pyrene (BaP), and naphthalene (Nap) were selected as the target analytes for CCQM-K131. These targets span the volatility range of PAHs found in environmental samples and include potentially problematic chromatographic separations. Nineteen NMIs participated in CCQM-K131. The consensus summary mass fractions for the three PAHs are in the range of (5 to 25) μg/g with relative standard deviations of (2.5 to 3.5) %. Successful participation in CCQM-K131 demonstrates the following measurement capabilities in determining mass fraction of organic compounds of moderate to insignificant volatility, molar mass of 100 g/mol up to 500 g/mol, and polarity pKow < −2 in a multicomponent organic solution ranging in mass fraction from 100 ng/g to 100 μg/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, and (3) separation and quantification using gas chromatography or liquid chromatography