BS EN 16175-1:2016 pdf free.Sludge, treated biowasteand soil – Determination ofmercury Cold-vapour atomic absorptionspectrometry (CV-AAS).
BS EN 16175-1 Mono- and divalent mercury is reduced to the elemental form by tin(Il) chloride or sodium borohydridein acid medium. Elemental mercury is stripped off from the solution in a closed system. The mercuryvapour, in the form of an atomic gas, passes through a cell positioned in the light path of an atomicabsorption spectrometer. lts absorbance at a wavelength of 253,7 nm is measured. The absorbancesignal is a function of mercury concentration, and the concentrations are calculated using a calibrationcurve.
NOTE The matrix of the solution analysed is dominated by the acids used in the digestion step. Tin(II)chloride as a reduction substance is recommended in this European Standard, because sodium borohydridereduces many elements commonly found in soil, sludge and waste extract solutions, to the elemental state, whichmay cause matrix problems under particular circumstances.However，it is still possible to use sodiumborohydride as reduction agent. The concentration range 1 ug/l to 10 ug/l in the digested solution,correspondingto 0,03 ug/g to 0,3 ug/g of mercury when a 3,0 g sample has been digested, can be determined directly. Higherconcentrations can be determined if the digested solution is diluted.Sensitivity can be increased by theamalgamation technique.
Because the samples are digested with oxidizing, strong acids before determination of mercury starts,there are no interferences with organic substances in the gas phase that can absorb in the UV range.Neither are there any interferences with mercury compounds which cannot be fully reduced with tin(1I)chloride alone. The interferences due to the presence of other elements in the matrix depend on theirconcentrations.Element concentrations exceeding those listed in Table 2 may cause negative bias.
Fewer interferences arise from heavy metals when tin(1l) chloride is used rather than sodiumborohydride.When flow systems are used, interference effects due to heavy metals may be less thanindicated in Table 2.
For the determination of mercury at trace and ultra-trace level, the reagents shall be of adequate purity.The concentration of mercury or interfering substances in the reagents and the water should benegligible compared to the lowest concentration of mercury to be determined.BS EN 16175-1 pdf download.