Selenium determination in biscuits and pasta: development of chronopotentiometric stripping determination by using a sulphide as an internal standard.

摘要: Abstract Being common in chromatographic techniques internal standard method is rarely applied electrochemical stripping determinations. One of the reasons for such rare use this elegant quantification because optimal conditions accumulation at electrode individual compounds producing a reproducible signal may vary significantly. These criteria are much stricter when selenium question due to very complex mechanism its mercury electrodes which implies simultaneous cathodic dissolution and chemical reaction. Elements that analytical step stripped cathodically from rare, further limiting application determination question. In work possibility using sulphide by chronopotentiometric analysis was investigated. Optimal experimental parameters were defined two-component systems. Dimensionless factors defining ratio proportionality constants two elements calculated different concentration ranges contents. Sulphide content chosen as adequate concentrations reasonably be expected food samples 500 µg/dm3. Determined detection limit an 0.04 µg/dm3 (RSD=7.6%; n=5). Defined confirmed analysing spiked solutions reference material. The used biscuit pasta samples. Calculated contents statistically compared with those obtained graphite furnace atomic absorption spectrometry.