ISO 17378-2:2014 pdf free

ISO 17378-2:2014 pdf free.Water quality一Determination of arsenic and antimony.
An aliquot of sample is acidified with hydrochloric acid (5.3). Potassium iodide-ascorbic acid reagent [5.9] is added to ensure quantified reduction of arsenic(V) to arsenic(I). The sample solutions are treated with sodium tetrahydroborate (5.5) to generate the covalent gaseous arsenic trihydride (arsine, AsH3). The hydride and excess hydrogen are swept out of the generation vessel in case of batch mode and out of the gas/liquid separator in case of the continuous mode into a heated silica cell. After atomization, the absorbance of arsenic is determined at a wavelength λ = 193,7 nm. The procedure is automated by means of auto-sampler and control software.
An aliquot of sample is digested with hydrochloric acid (5.3). Potassium iodide-ascorbic acid reagent (5.9) is added to ensure quantified reduction of the antimony(V) to antimony(III). The sample solutions are then treated with sodium tetrahydroborate (5.5) to generate the covalent gaseous antimony trihydride (stibane, SbH3). The hydride and excess hydrogen are swept out of the generation vessel in case of batch mode and out of the gas/liquid separator in case of continuous mode. After atomization, the absorbance of antimony is determined at a wavelength λ = 217,6 nm. The procedure is automated by means of auto-sampler and control software.
The hydride generation technique is prone to interferences by transition and easily reducible metals.
For the majority of natural water samples, this type of interference shalll not be significant. The user should carry out recovery tests on typical waters and also determine the maximum concentrations of potentially interfering elements, using appropriate methods. If such interferences are indicated, the level of interferences should be assessed by performing spike recoveries.
Metals which are readily reduced by sodium tetrahydroborate may also cause interferences. In particular, these include chromium, iron, copper, nickel, and lead. If the concentrations of these elements specified in Table 1 are exceeded, a significant decrease of absorption may occur.ISO 17378-2 pdf download.