[Show abstract][Hide abstract] ABSTRACT: The release of heavy metals from uncovered and nickel-covered brass pumps has been evaluated by ICP-MS analysis in both simple ultrapure water and 3% acetic acid solution (mimic of neutral and acid edible liquids, respectively), following a procedure similar to that recommended by the National Sanitation Foundation (NSF) International, Test Procedure P203. The results found highlight that the main release regards zinc, copper and lead, i.e. the three major metals present in brass alloys. The first contact of brass surfaces with the extraction solvent leads to an extensive Pb release which is comparable with that observed for Cu and Zn. Subsequent washings reduce markedly the Pb release, thus rising in evidence a progressive surface passivation. In particular, the Pb release found after four repeated washings turns out to approach the limit set by both Italian and USA governments for liquids used for food purposes when determined in neutral media, while it remains quite higher when evaluated in acid media. Release analyses conducted on nickel-covered brass pumps point out that the Niploy nickel coating process is very effective for brass surface protection, in that the Pb release is reduced of about three orders of magnitude, but a Ni release exceeding the relevant permitted level is in this case observed.
No preview · Article · Apr 2002 · Annali di Chimica
[Show abstract][Hide abstract] ABSTRACT: The effect on the formation of both oxygenated polyatomic and doubly charged ions in inductively coupled plasma mass spectrometry (ICP-MS) has been evaluated for sample introduction with three different injection devices. An ultrasonic nebulizer (USN) equipped with an efficient membrane desolvator, in addition to a usual desolvation module incorporating a heater and condenser, in comparison with both a concentric flow pneumatic nebulizer (PN) and the USN above without the mentioned additional membrane-desolvating module, offers the advantage of reducing markedly the relative abundance of both oxygenated polyatomic and doubly charged ions, thus leading to an overall improvement in the detection limits for the elements affected by their interferences. At the same time, detection limits for analytes unplagued by overlapping from these undesired ions remain unaffected since the additional membrane desolvator causes little or no sacrifice in the analyte signals, except for typically volatile elements, such as Se and Hg, whose detection limits worsen significantly.
No preview · Article · Nov 1999 · Annali di Chimica