Measurement of Uncertainty for Aqueous Ethanol Wet-Bath Simulator Solutions Used with Evidential Breath Testing Instruments.

Aqueous ethanol wet-bath simulator solutions are used to perform calibration adjustments, calibration checks, proficiency testing, and inspection of breath alcohol instruments. The Toxicology Bureau of the New Mexico Department of Health has conducted a study to estimate a measurement of uncertainty for the preparation and testing of these wet-bath simulator solutions. The measurand is identified as the mass concentration of ethanol (g/100 mL) determined through dual capillary column headspace gas chromatography with flame ionization detector analysis. Three groups were used in the estimation of the aqueous ethanol wet-bath simulator solutions uncertainty: GC calibration adjustment, GC analytical, and certified reference material. The standard uncertainties for these uncertainty sources were combined using the method of root-sum-squares to give uc = 0.8598%. The combined standard uncertainty was expanded to U = 1.7% to reflect a confidence level of 95% using a coverage factor of 2. This estimation applies to all aqueous ethanol wet-bath simulator solution concentrations produced by this laboratory.

Measurement of Uncertainty for Vaporous Ethanol Concentration Analyzed by Intoxilyzer® 8000 Instruments.

Reporting a measurement of uncertainty helps to determine the limitations of the method of analysis and aids in laboratory accreditation. This laboratory has conducted a study to estimate a reasonable uncertainty for the mass concentration of vaporous ethanol, in g/210 L, by the Intoxilyzer(®) 8000 breath analyzer. The uncertainty sources used were: gas chromatograph (GC) calibration adjustment, GC analytical, certified reference material, Intoxilyzer(®) 8000 calibration adjustment and Intoxilyzer(®) 8000 analytical. Standard uncertainties attributed to these sources were calculated and separated into proportional and constant standard uncertainties. Both the combined proportional and the constant standard uncertainties were further combined to an expanded uncertainty as both a percentage and an unit. To prevent any under reporting of the expanded uncertainty, 0.10 g/210 L was chosen as the defining point for expressing the expanded uncertainty. For the Intoxilyzer(®) 8000, all vaporous ethanol results at or above 0.10 g/210 L, the expanded uncertainty will be reported as ±3.6% at a confidence level of 95% (k = 2); for vaporous ethanol results below 0.10 g/210 L, the expanded uncertainty will be reported as ±0.0036 g/210 L at a confidence level of 95% (k = 2).

Determination of levamisole in urine by gas chromatography-mass spectrometry.

The United States Public Health Service Substance Abuse and Mental Health Services Administration is alerting medical professionals that a substantial percentage of cocaine imported into the United States is adulterated with levamisole, a veterinary pharmaceutical that can cause blood cell disorders such as severe neutropenia and agranulocytosis. Levamisole HCl is the active ingredient in a number of veterinary drugs approved to treat worm infestations in animals. Levamisole HCl was also the active ingredient in a human drug for oral administration approved on June 18, 1990, as adjuvant treatment in combination with fluorouracil after surgical resection in patients with Duke's stage C colon cancer. This drug was withdrawn from the U.S. market around 2000, and it has not been marketed in the U.S. since then. The objective of this study was to develop a method to determine the amount of levamisole in urine samples. The procedure will be provided to state health laboratories as needed to be used in the evaluation of patients that have developed neutropenia or agranulocytosis in the setting of recent cocaine use. A gas chromatography-mass spectrometry method was validated and tested at two different laboratories, and the method limit of detection for levamisole is 1 ng/mL in urine when using a 5-mL sample. Confirmation of the stereoisomer of levamisole was done by high-performance liquid chromatography using a chiral column.