Determination of methylisothiazolinone and methylchloroisothiazolinone in cosmetic products by ultra high performance liquid chromatography with tandem mass spectrometry.

Isothiazolinone biocides are broad-spectrum preservatives that are widely used in cosmetics, household, and industrial products. An increase in the number of cases of allergic contact dermatitis to isothiazolinone preservatives, namely, methylisothiazolinone and methylchloroisothiazolinone, have been recently noticed. The Food and Drug Administration relies on analytical methods to quantify levels of use of cosmetic ingredients and support enforcement action against products that are not in compliance with the law. In this study, an efficient ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the determination of methylisothiazolinone and methylchloroisothiazolinone in selected cosmetic products. The lower limit of quantitation was determined to be 0.1 µg/g for both preservatives. A survey of 24 cosmetic products was conducted and found concentrations of methylisothiazolinone and methylchloroisothiazolinone ranging from not quantified, or below the lower limit of quantitation, to 89.64 µg/g and not quantified to 10.31 µg/g, respectively.

Lead in women's and children's vitamins.

A survey was conducted to determine the extent of lead (Pb) contamination in vitamins labeled for use by women and children. The Pb content of 324 multivitamin-mineral products was determined using microwave assisted nitric acid digestion and inductively coupled plasma mass spectrometry. Cryogenic grinding was used to composite soft samples such as oil filled capsules and candy-like products such as gummies and jelly beans. Estimates of Pb exposures from consumption of these products were derived for four population groups: young children (0-6 yrs), older children (7+ yrs), pregnant or lactating women, and adult women. The estimated median and maximum Pb exposures were 0.123 and 2.88 microg/day for young children, 0.356 and 1.78 microg/day for older children, 0.845 and 8.97 microg/day for pregnant and lactating women, and 0.842 and 4.92 microg/day for adult women. The overall median value for Pb exposure was 0.576 microg/day. Five samples would have provided exposures that exceeded 4 microg/day. Estimates of exposures were assessed with respect to safe/tolerable exposure levels that have been developed for the specific age and sex groups. These safe/tolerable levels are referred to as the provisional total tolerable intake levels (PTTI) and are 6, 15, 25, and 75 microg Pb/day for young children, older children, pregnant or lactating women, and adult women, respectively. Estimates of Pb exposures were below the PTTI levels for the four population groups. Median and maximum values were used instead of the mean and standard deviation because of the skewed distribution of results toward lower mass fraction and exposure.