B. Matuszewski, “Standard Line Slopes as a Measure of a Relative Matrix Effect in Quantitative HPLC-MS Bio- analysis,” Journal of Chromatography B, Vol. 830, No. 2, 2006, pp. 293-300. doi:10.1016/j.jchromb.2005.11.009

has been cited by the following article:

• TITLE: Liquid Chromatography-Tandem Mass Spectrometry Assay to Detect Ethyl Glucuronide in Human Fingernail: Comparison to Hair and Gender Differences

  AUTHORS: Joseph Jones, Mary Jones, Charles Plate, Douglas Lewis, Michael Fendrich, Lisa Berger, Daniel Fuhrmann

  KEYWORDS: Alcohol; Biomarkers; Liquid Chromatography-Tandem mass Spectrometry; LC-MS/MS; Ethyl Glucuronide; Fingernail; Hair

  JOURNAL NAME: American Journal of Analytical Chemistry, Vol.3 No.1, January 5, 2012

  ABSTRACT: Over the past decade, the use of hair specimens for the long-term detection of the alcohol biomarker ethyl glucuronide has been increasing in popularity and usage. We evaluated the usefulness of fingernail clippings as a suitable alterna-tive to hair for ethyl glucuronide detection. A liquid chromatography-tandem mass spectrometry method for the detection of ethyl glucuronide in fingernail clippings was fully validated and used to analyze the hair and/or fingernail specimens of 606 college-aged study participants. The limit of detection was 2 pg/mg, the limit of quantitation was 8 pg/mg and the method was linear from 8 to 2000 pg/mg. Intra- and inter-assay imprecision studies at three different concentrations (20, 40, 200 pg/mg) were all within 7.8% and all intra- and inter-assay bias studies at these levels were within 115.1% of target concentration. Ethyl glucuronide levels in fingernail (mean = 29.1 ± 55.6 pg/mg) were higher than ethyl glucuronide levels in hair (mean = 9.48 ± 22.3 pg/mg) and a correlation of the matched pairs was observed (r = 0.552, P