J. Cosmet. Sci., 63, 159–176 (May/June 2012) 159 Determination of total lead in 400 lipsticks on the U.S. market using a validated microwave-assisted digestion, inductively coupled plasma-mass spectrometric method NANCY M. HEPP, Offi ce of Cosmetics and Colors, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD 20740. Accepted for publication November 8, 2011. Synopsis In 2009, the U.S. Food and Drug Administration (FDA) published lead (Pb) content results from a small survey of 20 tube lipsticks with red shades using a validated inductively coupled plasma-mass spectromet- ric (ICP-MS) method developed by FDA chemists. The study was prompted by a media report suggesting that potential exposure to lead from lipsticks under conditions of ordinary use might be harmful. The FDA has since investigated the lead content of tube lipsticks by conducting an expanded survey that included a variety of shades and manufacturers, at varying prices. The purposes of the expanded survey were to ascer- tain the levels of lead in lipsticks sold on the U.S. market, to identify any categories of lipstick with ele- vated levels of lead, and to compare the results to those from the initial small survey. Four hundred lipsticks available on the U.S. market in the spring of 2010 were tested for total lead content using the FDA’s validated method. The analyses were performed by a private laboratory contracted by the FDA. The maximum lead level found was 7.19 mg Pb/kg. Thirteen of the 400 lipsticks were found to contain levels greater than 3.06 mg Pb/kg, the highest amount found in the initial survey. The average lead concentration found in the expanded survey was 1.11 mg Pb/kg, which was very close to the average of 1.07 mg Pb/kg found in the initial survey. Some statistically signifi cant associations between lead level and parent company were found. The contract requirements, testing procedures, and fi ndings from the expanded survey are de- scribed here. INTRODUCTION In 2009, the FDA published an initial survey of lead (Pb) content in 20 tube lipsticks with dark red shades, using a validated inductively coupled plasma-mass spectrometric (ICP-MS) method developed at the FDA (1,2). Several media reports (3–6) had generated a large number of consumer inquiries regarding the safety of lipsticks with respect to lead, and the FDA’s validated method was intended for independent assessment of the lead contamination. FDA scientists also had concerns that values reported by the media were produced using a variety of methods that could give dramatically different lead values depending on how the sample was treated. We noted that in at least one case sul- furic acid, an acid that will precipitate lead and make it unavailable for analysis, was used in extraction mixtures.

JOURNAL OF COSMETIC SCIENCE 160 Analytical techniques requiring a solubilized analyte fall into two preparation catego- ries: (a) acid extraction of the analyte from the sample matrix, or (b) total destruction of the matrix. We chose to use a total matrix destruction technique for the validated method. Nitric acid has the desirable properties that at high temperatures can break down organic (carbon-based) molecules such as the oils and waxes in lipstick, and it also solubilizes lead as lead nitrate. Nitric acid, however, will not break down certain inor- ganic minerals, such as talc, mica, or titanium dioxide, which are commonly used in lipstick. In developing a method, we found that not all the lead was extracted from lip- stick with nitric acid alone. After trying several total matrix destruction methods, we modifi ed a method developed by scientists at the Cosmetics, Toiletries, and Fragrances Association (currently the Personal Care Products Council) that included a hydrofl uoric acid step for breaking down the inorganic minerals (7). We then found it necessary to add an excess of boric acid to dissolve the resultant insoluble fl uorides. Analyses of the resulting clear solutions by inductively coupled plasma-mass spectrometry (ICP-MS) gave reproducible lead values even under changing preparation conditions, such as using higher maximum digestion temperatures or reduced portion sizes. We used the method to determine lead in the initial survey of 20 lipsticks. Because the initial survey was small and from a limited segment of products, the FDA decided that an expanded survey of the U.S. lipstick market was needed. Since the FDA had limited time and personnel for the task, a contract laboratory was solicited to perform the study using the validated method. EXPERIMENTAL SELECTION OF CONTRACTOR The contractor was awarded a contract for the expanded survey on September 15, 2009, based on its demonstrated experience with lead analyses in matrices similar to lipstick and the availability of appropriate facilities, equipment, and personnel to meet technical, time, and budget criteria. Prior to analyzing the lipstick samples, the contractor was asked to demonstrate its ability to obtain values that agreed with those for three reference lipsticks, as well as to meet specifi c performance criteria regarding limit of detection, quality control, and precision. LIPSTICK SAMPLING Lipsticks for the expanded survey were selected by choosing manufacturers, brands, and shades that refl ected the products currently on the market. This was accomplished by proportioning the number of lipsticks chosen from each brand to its market share using data from the 2008 Euromonitor Report (8). A few additional lipsticks were selected from niche markets in an effort to capture lipsticks with unusual characteristics. A total of 400 lipsticks with a variety of shades, with no particular targeted colors, were selected from 24 parent companies. One pair of lipsticks per manufacturer with the same lot num- ber (and therefore the same shade) was collected as an additional test of lot homogeneity. Each of the 400 lipsticks was tested in duplicate.