Automated headspace solid-phase dynamic extraction for the determination of cannabinoids in hair samples

This article describes a fully automated procedure for detecting cannabinoids in human hair samples. The procedure uses alkaline hydrolysis and headspace solid-phase dynamic extraction (HS-SPDE), followed by on-coating derivatization and gas chromatography-mass spectrometry (GC-MS). SPDE is a further development of solid-phase microextraction (SPME), based on an inside needle capillary absorption trap. It uses a hollow needle with an internal coating of polydimethylsiloxane as extraction and pre-concentration medium.Ten mg of hair were washed with deionised water, petroleum ether and dichloromethane. After adding deuterated internal standards, the sample was hydrolyzed with sodium hydroxide and directly submitted to HS-SPDE. After absorption of analytes for an on-coating derivatization procedure, the SPDE-needle was directly placed into the headspace of a second vial containing N-methyl-N-trimethylsilyl-trifluoroacetamide before GC-MS analysis. The limit of detection was 0.14 ng/mg for Delta(9)-tetrahydrocannabinol, 0.09 ng/mg for cannabidiol, and 0.12ng/mg for cannabinol. Absolute recoveries were in the range of 0.6 to 8.4%. Linearity was verified over a range from 0.2 to 20 ng/mg, with coefficients of correlation between 0.998 and 0.999. Intra- and inter-day precision were determined at two different concentrations and resulted in ranges between 2.3 and 6.0% (intra-day) and 3.3 and 7.6% (inter-day). Compared with conventional methods of hair analysis, this automated HS-SPDE-GC-MS procedure is substantially faster. It is easy to perform without using solvents and with minimal sample quantities, and it yields the same sensitivity and reproducibility. Compared to SPME, we found a higher extraction rate, coupled with a faster automated operation and greater stability of the device.     

Private Sentiments in a Public Context: Aspects of Co-operative Housing in Oslo

The subject of the article is the Oslo model of co-operative housing. A cooperative model may be considered a predominantly 'public' solution, or given a more 'private' flavor, depending on the different forms given to the co-operative idea. This article considers the political consequences of alternative implementations. It presents a historical survey of the initial reactions of the tenant urban working class to the insecurities of the housing market, its inevitable clash with landlord interests, and the earlier varieties of radical and socialist responses to the housing misery. The search for a 'public' form of ownership leads to the gradual acceptance of the co-operative solution, and the rise of one co-operative organisation (OBOS) from a position of modesty to one of dominance. The administrative principles employed in the distribution of apartments lead to a number of unexpected consequences relating to the rights of the members and owners. While the OBOS administration is engaged in limiting the contagion of the 'free market', it is also concerned not to antagonize the opinions of the members. These conflicting interests lead to a number of administrative knots, particularly since new sentiments among both old and more recent members press towards a 'private' interpretation. The political parties react to these sentiments in the electorate in different ways, but with deep concern for the increasing interest in ownership.