The Migration of Elements from Toys andSpeciation of Chromium (Vl) in Toy MaterialUsing a IC-ICP-MS Solution

Key Words

Chromium, lon Chromatography (lc), Speciation，Toys

Goal

To answer the need for trace level determination of several elements andhexavalent chromium that migrate from toy materials at limits outlined inEU directive 2009/48/EC.

lntroduction

Hexavalent chromium (Cr ( VI)) is highly toxic and classedas a carcinogen.Trivalent chrormnium (Cr (llIy), however, isessential for enzymatic function in human metabolism.Discrimination between the oxidation states is thereforeessential for an accurate risk assessment of chromium inmaterials we are exposed to.

The European Union directive for toy safety (2009/48/EC)is currently under revision,and the proposed limits forCr (Vl) content are analytically challenging with commonly used methods.For example, High PressureLiquid Chromatography (HPLC) coupled to InductivelyCoupled Plasma Mass Spectrometry (ICP-MS) may not besuitable as high elemental chromium backgrounds push detection limits above theaatography (IC) is shown to be a powerful alternative to HPLG, allowing the analysis of both Cr species in the low ng L ' range. Although ICchromatographic separation of the two species is simple,sample preparation plays an important role.Depending onsample conditions (e.g-pH), inter species conversion mayoccur prior to quantification producing inaccurate speciesdistribution. In this application note, we present a methodfor total elemental quantification(TEQ) and for stabilization and quantification of Cr (VI) after migrationfrom toy material and its sensitive detection at the 2009/48/EC directive required levels.

Sample and Calibration Solution Preparation

Three different samples were analyzed; finger paint, penink and a titanium dioxide (TiO,) raw material that iscommonly used as a white pigment in many different toyproducts.

To evaluate the method for the determination of totalelemental concentrations, each element outlined in theEU directive was spiked into the finger paint sample atdifferent concentrations and analyzed by ICP-MS.All samples were subjected to the migration process asdescribed in the European Standard EN 71-3:2012'.ThisStandard Operating Procedure (SOP) has been recentlyupdated and at the time of publication of this applicationnote has not been officially released to the public.

In themigration solution,Cr (VI is prone to slow reduction inthe acidic environment and a stabilization step is necessary after migration is completed to maintain theoriginal species distribution.