a b s t r a c tA solid phase extraction sorbent, aminopropyl triethoxysilane-functionalized silica was prepared and used for vanadium speciation prior to inductively coupled plasma mass spectrometric determination. The necessary sorption parameters such as sorption pH, reaction temperature, sorbent amount and sample volume were optimized. The sorption for V(V) and V(IV) under the optimized conditions was 98% (±1) and was lower than 10%, respectively. The sorption process was investigated both from a kinetic perspective and also in terms of Freundlich, Dubinin-Radushkevich and Langmuir isotherm models to characterize the uptake of vanadate ion by the functionalized silica. Desorption from the sorbent was realized with 0.5 mol L −1 thiourea prepared in 0.2 mol L −1 HCl. Among the possible interfering species tested, Te(IV), Se(IV), Se(VI) and Fe(III) showed interference effects with V(V) signal. The validity of the method was first checked via spike recovery experiments with four different types of water; namely ultra pure, bottled drinking, tap, and sea water for different concentrations of V(V). The percent recovery values changed between 87 and 108 for all water types. The accuracy of the proposed methodology was also checked by analyzing a standard reference material (NIST, SRM 1643e) and a good agreement was found between the determined and the certified value. The proposed methodology has also been shown to be applicable for the separate sorption of V(V) in the absence/presence of V(IV) and for the sorption of both V(IV) and V(V) in waters. The amount of V(IV) can then be determined from the difference.

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A separation method utilizing a synthetic zeolite (mordenite) was developed in order to eliminate the gas phase interference of Sb(III) on As(III) during quartz furnace hydride generation atomic absorption spectrometric (HGAAS) determination. The efficiency of the proposed separation method in the reduction of suppression effects of transition metal ions on As(III) signal was also investigated. Among the volatile hydride-forming elements and their different oxidation states tested (Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), and Te(VI)), only Sb(III) was found to have a signal depression effect even at low (g l −1 ) concentrations under the experimental conditions employed. It has been shown that mordenite adsorbs Sb(III) quantitatively, even at a concentration of 1000 g l −1 , at pHs greater than two, and also, it reduces the initial concentrations of the transition metal ions to lower levels which can be tolerated in many studies. The adsorption of Sb(III) on mordenite follows the Freundlich isotherm and is endothermic in nature.

The widespread of individual and social problems related to substance use/abuse provoked the new approaches for workplace drug testing systems in the world. Workplace drug testing laws are constructed to protect the community from the consequences of drug use by workers. In Turkey, the legal arrangements on workplace drug testing exist in Turkish Penal Code, Turkish Labour Law, Workplace Physicians Regulations, Maritime Labour Law and Medical Examination Instructions in Highway Transportation Although Turkey has made the initial attempts to develop homogeneous and reliable regulations for workplace drug testing, a detailed workplace policy for drug testing at workplace has still not been provided.. An amendment has been done in the Regulations on Seafarers and a drug test (marijuana, cocaine, amphetamine like drugs and opiate) has been added into the routine tests to take a "Seafarer Health Report".

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