1 kg composite sample and an equivalent mass of deionized water (for Type I products) or
10% nitric acid (Type II products) were placed in a large sized Nalgene polymethylpentene
mixing vessel. The mixture was covered and left overnight to facilitate softening/dissolution of
the product. In some cases, heating was required to assist in this process. The resulting mixture
was blended in a 6 L stainless steel bowl of a Robot Coupe RSI 6Y food chopper until a visually
homogeneous mixture was obtained. In the case of chocolate-based products, smaller amounts
of water were required to avoid formation of water-insoluble fat layer. In the case of Type II,
IIA, and III products, the mixture was subjected to an additional blending step using a high-shear
type Brinkmann Polytron mixer to facilitate homogenization of remaining particulate materials
in the mixture. It should be noted that although some candy additives such as silicon dioxide and
titanium dioxide may not be completely dissolved after this treatment process, this process
provides a mixture that is homogeneous with respect to lead content and stable enough to allow
selection of a subsample for subsequent digestion and analysis.