Gas-liquid chromatographic (GLC) determination of vitamin D in multivitamin preparations was investigated and a simple routine method was established. The unsaponifiable matters of a sample was applied to a thin-layer chromatography (TLC) plate using Kieselgel GF₂₅₄ as an adsorbent and a mixture of n-hexane-ethyl acetate (4:1) as a developing solvent. The scraped zones corresponding to vitamin D and previtamin D were extracted and determined by GLC using 1.5 OV-17 packed on Shimalite w (80-100 mesh) as a stationary phase. When the proposed method was applied to model preparations made by mixing vitamin D, A and E, it was confirmed that the determination of vitamin D was possible when the ratios of vitamin A and E (DL-α-tocopheryl acetate) to vitamin D were within 104 (I. U, ratio) and 2, 500 (weight ratio), respectively. Since the ratios of most of commercial multivitamin preparations on sale in Japan are within the limitations and the results on multivitamin preparations were also satisfactory, the proposed method was confirmed to be suitable simple routine.

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Our modern world is moving towards a ‘ New Urban World'. More people than ever before are living in urban areas and modern cities are becoming powerhouses of creative ideas, innovative technologies, sustainable developments and socioeconomic wealth in an open and globalizing economy. And most likely this trend will continue. Cities will also play a pivotal role in the future of an urbanized Europe, although they are certainly confronted with grand challenges. Emerging threats to urban environments may, however, be turned into new opportunities. Thus, urban areas may act as spearheads of sustainable economic growth for European countries. This paper will offer a novel contribution to the assessment of the socio-economic performance of 9 selected European cities in the North Sea basin over two time periods. The exploration of the socio-economic benefits of these cities leads to the definition of a ‘ democratic beauty', whereas urban performance is measured along multiple dimensions. We will evaluate their performance and rank their relative efficiency performance using a new variant of Data Envelopment Analysis (DEA), through which we are also able to further discriminate between the class of efficient Decision Making Units by introducing the notion of super-efficiency. The ‘ winners' in this competitive assessment of highly efficiently cites are labeled here as incredible cities. The paper will be concluded with some policy recommendations.

JEL Classification: O47, R12

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