An evaluation of analytical techniques for determination of lead, cadmium, chromium, and mercury in food-packaging materials.
Closed microwave digestion and a high-pressure asher have been evaluated for wet-oxidation and extraction of lead, cadmium, chromium, and mercury from a range of typical packaging materials used for food products. For the high-pressure asher a combination of nitric and sulfuric acids was efficient for destruction of a range of packaging materials; for polystyrene, however, nitric acid alone was more efficient. For microwave digestion, a reagent containing nitric acid, sulfuric acid, and hydrogen peroxide was used for all materials except polystyrene. Use of the high-pressure asher resulted in the highest recoveries of spiked lead (median 92%), cadmium (median 92%), chromium (median 97%), and mercury (median 83%). All samples were spiked before digestion with 40 microg L(-1) Cd, Cr, and Pb and 8 microg L(-1) Hg in solution. The use of indium as internal standard improved the accuracy of results from both ICP-MS and ICP-AES. Average recovery of the four elements from spiked packaging materials was 92 +/- 14% by ICP-MS and 87 +/- 15% (except for mercury) by ICP-AES. For mercury analysis by CVAAS, use of tin(II) chloride as reducing agent resulted in considerably better accuracy than use of sodium borohydride reagent.
Perring
L
L
Quality and Safety Assurance Department, Nestlé Research Centre, Lausanne, Switzerland. loic.perring@rdls.nestle.com
Alonso
M I
MI
Andrey
D
D
Bourqui
B
B
Zbinden
P
P
D001894:Borohydrides; D002104:Cadmium / Q000032:analysis*; D002857:Chromium / Q000032:analysis*; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis*; D019649:Food Industry / Q000592:standards; D018857:Food Packaging / Q000592:standards*; D007854:Lead / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods; D008452:Maximum Allowable Concentration; D008628:Mercury / Q000032:analysis*; D008872:Microwaves; D017942:Nitric Acid / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry; D013054:Spectrophotometry, Atomic / Q000379:methods; D013464:Sulfuric Acids / Q000737:chemistry; D017971:Tin Compounds / Q000737:chemistry
D001894:Borohydrides; D011137:Polystyrenes; D013464:Sulfuric Acids; D017971:Tin Compounds; D002104:Cadmium; D002857:Chromium; C023599:stannous chloride; D007854:Lead; D017942:Nitric Acid; C025364:sodium borohydride; D008628:Mercury; C033158:sulfuric acid