Overview
Grembecka and Szefer measured 14 elements by flame atomic absorption in 148 confectionery samples bought in Gdansk, then used factor and cluster analysis to separate product types. Lead and cadmium were not detected in any product at the method’s detection limits. Chromium, nickel and cobalt were quantified in cocoa and chocolates. All results are on a wet-weight basis.
Key numbers
- Lead and cadmium: “ND” in all 13 product types, including 46 dark chocolates, 24 milk chocolates and 3 milk chocolates with peanuts; detection limits 0.01 mg/100 g (lead) and 0.003 mg/100 g (cadmium) wet weight (Table 6, p. 254; Methods p. 251).
- Cocoa (n = 24): nickel 1.26 ± 0.30 mg/100 g, chromium 0.51 ± 0.29 mg/100 g (Table 6).
- Dark chocolate (n = 46): nickel 0.31 ± 0.17 mg/100 g (0.19 to 0.79); milk chocolate with peanuts (n = 3): nickel 0.06 ± 0.004 mg/100 g (Table 6).
Methods (brief)
Three replicates of about 1 g per sample were microwave-digested in nitric acid and read by flame atomic absorption with deuterium background correction. Accuracy was checked against tea, cabbage and spinach reference materials (recoveries 73.5 to 103 percent, Table 2).
Evidence Fitness
A moderate market sample, but flame atomic absorption has high detection limits for lead (about 0.1 mg/kg) and cadmium (about 0.03 mg/kg), so the non-detects are not informative at current regulatory levels. The Methods text says chromium, nickel and cobalt were below detection, which conflicts with the quantified values in Table 6; values are recorded as printed. Milk chocolate with peanuts is a direct but tiny (n = 3) measurement for chocolate nut candy. Chocolate results are a proxy for chocolate pudding and fruit snack candy, and those pages are not linked.