A homologous series of internal standards for near universal application in the discovery LC-MS/MS bioanalytical laboratory.

When using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) to quantify In Vivo samples, an internal standard (ISTD) is key in correcting for variability within the sample extraction process and injection volume. Just as important is the ability of the internal standard to identify any matrix effects, which can artificially suppress or enhance the signal of the compound of interest. To properly do this, the internal standard should co-elute with the compound. A common source of potential matrix effects with In Vivo studies is from the excipient(s) used to formulate the compound for dosing. In the world of high-throughput discovery bioanalysis, a lab can quantitate over a hundred compounds each week, many of which are evaluated once, and rarely is a stable-isotope labeled (SIL) internal standard available (the industry gold standard). Finding a suitable and easy-to-use alternative LC-MS/MS method is important to providing high quality data. To overcome this challenge, a homologous series of compounds was synthesized to improve the chromatographic range for co-eluting ISTD's. This novel mix of internal standards was shown to have key characteristics making it ideal for use as a near universal internal standard mix including but not limited to: they ionize in both positive and negative modes, they are susceptible to signal perturbation from common formulation excipients, and they cover a wide range of retention times.

Detection of codeine, morphine, 6-monoacetylmorphine, and meconin in human umbilical cord tissue: method validation and evidence of in utero heroin exposure.

BACKGROUND: Heroin abuse is a significant public health issue and is on the rise because of the unintended consequences of strengthening controls for nonmedical use of prescription pain killers. Included in this trend is an increase in opiate exposed newborns that are particularly vulnerable to a number of negative health outcomes. METHODS: After presenting a fully validated liquid chromatography-tandem mass spectrometric method for codeine, morphine, 6-monoacetylmorphine, and meconin, a metabolite of the heroin contaminant noscapine, we compared the outcome of 46 authentic umbilical specimens with the results generated using a previous less sensitive method that did not include meconin. Additionally, we provided a summary of opiate finding from a year-long survey of specimens received into a commercial reference laboratory. RESULTS: The limits of detection for all 4 compounds were 0.1 ng/g, the limit of quantitation was 0.2 ng/g, and the assay was linear from 0.2 to 10.0 ng/g. Of the 46 comparative specimens, this method improved the identification of heroin exposure from 2 to 5, and the year-long survey identified 86 heroin-exposed newborns with 11 of them identified by the sole identification of meconin. CONCLUSIONS: This study demonstrated that a more sensitive analytical platform and the inclusion of meconin in the opiates assay improved the ability to distinguish between in utero heroin exposure and maternal administration of codeine or morphine.