ACTA TECHNICA CORVINIENSIS – BULLETIN of ENGINEERINGACTA TECHNICA CORVINIENSIS– BULLETIN of ENGINEERINGcopyright ©UNIVERSITY POLITEHNICA TIMISOARAFACULTY OF ENGINEERING HUNEDOARA5, REVOLUTIEI331128 – HUNEDOARAROMANIAhttp://acta.fih.upt.ro122009/Fascicule 2/April‐June/Tome II
1.I. DAVID, 2.. F. BERBENTEA, 3. M. ŞTEFANUŢ, 4. L. GEORGESCU,5.G.BUJANCĂ, 6. T.TRAŞCĂ, 7. M.DANCI, 8. OANA DANCITHE HEAVY METALS MONITORINGIN CANNED VEGETABLES MIXAbstract:The paper proposes some possibilities for heavy metals detection in canned vegetables mix: Cr, Fe,Pb, Cd, Sn, Al, Zn, As . The heavy metals concentrations have been determinate by AA spectrometryand electrochemical methods: cyclic voltammetry. The monitoring of heavy metals in cannedvegetables mix can help evaluate and improve the insufficiently developed technology.Keywords:vegetables mix, heavy metals, AA spectroscopy, cyclic voltammetryINTRODUCTIONVegetables mix and similar products are widelyused for taste enhancement of various foodproducts. Apart from their taste properties theyalso have a high nutritive value due to thecontent of easily retainable sugars, vitamin C,carotenoids and mineral salts.Vegetables mix is a produce conserved throughdecrease in humidity, thus preventing theevolution of microorganisms. Microorganismsrequire a certain minimum amount of water todevelop; bacteria require 35%, yeasts 25% andmolds only need 10%.EXPERIMENTALSamples preparationVegetables mix products have been weighed andtreated by concentrated nitric acid (67%, Merck,heavy metals free). Samples digestion has beenachieved in a 1000W MWS-2 – Berghof typemicrowave oven using a three-step program:T 1 =160ºC, t 1 =15 min., P 1 =40-60% from totalpower, T 2 =210ºC, t 2 =15 min., P 2 =60-80%,T 3 =210ºC →100ºC, t 3 =15 min., P 3 =0%.Thusresulted solutions have been completed withultrapure water (RO System OperatingBarnstead apparatus) to equal volumes in 25 mlcalibrated flasks.Methods of analysis. AA SpectrometryThe heavy metals content has beendeterminated by AA spectrometry (InternationalStandard ISO 15586:2003) and cyclic voltametry(Koryta , 1993), i=f(E). AA spectrometry has beenachieved with novAA 400 G type spectrometer -Analytik Jena - Germany, equipped with graphitefurnace, WinAAS 3.17.0 software for evaluation,control and result presentation, a so-calledcookbook, for every element, and a HS 55-1hydride generator. Calibration curves have beenplotted using standard solutions of metals insearch.Electrochemical MethodsHeavy metals such as Sn, Fe, Zn at the electrodesurface are affcted by characteristic redoxphenomena with can be used to determine their© copyright FACULTY of ENGINEERING – HUNEDOARA, ROMANIA 13