Vanadium(V) in the form of NH4V03 or as an aqueous solution of V205 (pH > 9, ammonia solution) has been studied as a modifier for 25 analyte elements of high and moderate volatility. The maximum pre-treatment temperatures ("C) in the presence of 20 pg of V V and 20 pg of VV + 4 pg of Pdll are, respectively: Ag (900 and 1000); Al (1400); As (1450 and 1450); Au (850 and 1000); Bi (850 and 1200); Cd (800 and 800); Co (1100); Cr (1000); Cu (1000and 1150); Fe(1550); Ga (1100and 1350); Ge(900and 1350); Hg(290); In (1100and 1300); Ni (1100); Mn(1000and 1300); P(1500and 1550); Pb(900and 1000); Pd(1400);Sb(1000and 1400);Se(1550and 1400); Sn (1300 and 1400); Te (700 and 1500); TI (1050 and 1100); and Zn (850 and 900). A high efficiency of thermal stabilisation by the mixed modifier V + Pd has been observed for most volatile analytes.Investigations using the modifier have been carried out on slurried and digested biological and environmental reference materials.

The commonly used parameters characterizing fuel cells and in particular microbial fuel cells (MFCs) electrical performance are open circuit voltage (OCV), maximum power, and short circuit current. These characteristics are usually obtained from polarization and power curves. In the present study, the expanded uncertainties of operational characteristics for yeast‐based fuel cell were evaluated and the main sources of uncertainty were determined. Two approaches were used: the uncertainty budget building for sources uncertainty estimation and a statistical treatment of identical MFCs results – for operational characteristics uncertainty calculation. It was found that in this particular bioelectrochemical system the major factor contributing to operational characteristics uncertainties was the electrodes' resistance. The operational characteristics uncertainties were decreased from 19 to 13% for OCV, from 42 to 14% for maximal power, and from 46 to 13% for short circuit current with the usage of electrodes with resistance in the interval 6–7 Ω. The described approaches can be used for operational characteristics expanded uncertainties calculation of all types of fuel cells using data from polarization measurements.

The applicability of different chemical modifiers for thermal stabilization and ETAAS determination of mercury is studied. The modifier effect is strongly influenced by the type of acid and acid content in the sample solution. A method is described for mercury determination in tuna fish and sediment after high pressure digestion with nitric acid, using thioacetamide (TAC) as chemical modifier. The method permits determination of 0.5 pg g-' mercury. A simpler and faster procedure using a slurry technique for the determination of mercury in reference materials (tuna fish, spinach, cabbage and sediments) was also evaluated. Optimal instrumental parameters for mercury determination in slurries are presented. On the basis of the results obtained a new procedure which allows determination of 0.1 pg g-' mercury was developed.

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