A method was developed to determine the levels of two intense sweeteners, saccharin and acesulfame-K, in human urine. Measurement of these two analytes in urine allowed an assessment to be made of dietary exposure to the sweeteners using intake/excretion curves. This paper describes an intake/excretion study in which 22 volunteers consumed known amounts of saccharin and acesulfame-K at five different levels ranging between 1.4 and 70 mg of saccharin (0.7-30% of the ADI for a 60 kg person) and 2.2-102 mg of acesulfame-K (0.4-19% of the ADI for a 60 kg person). Urine collections were then carried out by the volunteers for 24 h after each dose. The data obtained from this study were used to construct intake/excretion curves for both sweeteners. To test the methodology developed, 188 volunteers aged between 3 and 74 years were asked to carry out a 24-h urine collection whilst keeping a 48-h food diary. Comparison of the intake data obtained using the biomarker approach with the questionnaire-based results was generally good, although discrepancies due to the format and assessment of the questionnaire data were noticed.

An interlaboratory study of a graphite furnace atomic absorption spectrophotometry (GFAAS) method for the determination of lead in wine was conducted. Seventeen laboratories from France, United States, and the United Kingdom, using a variety of GFAAS instruments, took part in the study. The method incorporated a novel matrix-matching procedure to minimize matrix effects between standards and samples. Six wine test materials were prepared and sent to participants as 12 blind duplicate or split level samples. There was good agreement between results obtained from participants and target values (24–279 μg/L) obtained with an inductively coupled plasma-mass spectrometry method. The precision of the GFAAS method was well within the range predicted by the Horwitz equation for the 6 test materials analyzed. Repeatability standard deviations ranged from 3 to 17%. Reproducibility standard deviations were in the range of 10 to 30%. The method is recommended for use for official purposes.