Urine Standard Reference Material Research Articles

NIST reference materials to support accuracy in drug testing

Substance abuse is a major problem worldwide. There is considerable emphasis placed upon testing individuals for evidence of use of controlled substances. Because the consequences of a positive test can be quite severe, laboratories conducting such tests must rigorously follow a carefully designed quality assurance program. Such a QA program should include use of reference materials to assure that the methods used to detect and quantify drugs are providing accurate results. The National Institute of Standards and Technology (NIST) supports accuracy in drugs of abuse testing by providing Standard Reference Materials (SRMs) with certified concentrations of drugs of abuse in urine- and hair-based reference materials. NIST, working in collaboration with the College of American Pathologists (CAP), has developed urine-based SRMs for marijuana metabolite, cocaine metabolite, morphine and codeine, and morphine glucuronide and CAP Reference Materials for amphetamines and phencyclidine. Certification measurements performed at NIST involve two independent methods for each analyte, one of which always uses GC/MS with the other usually being an LC method with either MS or UV detection. Work has recently been completed on a seven component drug in urine SRM. In addition NIST conducts research in the analysis of hair for drugs of abuse. To assist laboratories testing hair for that purpose, NIST has developed two drugs in hair reference materials.

Helium inductively coupled plasma-mass spectrometry: studies of matrix effects and the determination of arsenic and selenium in urine

This study on helium inductively coupled plasma-mass spectrometry (He ICP-MS) is concerned with three related issues. First, a boron nitride sampler was explored for reducing the extent of the secondary discharge prevalent in He ICP-MS. Second, an investigation of matrix effects was conducted by adding increasing concentrations of Na, U and SO 4 2− to solutions containing As + and Br + as the analytes. Third, the practical utility of He ICP-MS was explored for the determination of As and Se in a urine standard reference material (NIST SRM 2670). The major observations were: (1) the most probable ion kinetic energy for 75As + was 15 eV with a boron nitride sampler for an 800-W He ICP, similar to the results achieved when an aluminum sampler was used for He ICP-MS, but higher than the kinetic energies that are typically reported for Ar ICP-MS; (2) enhancement of As and Br signals by Na, U and SO 4 2− were observed, but the enhancement effects could be corrected by the use of Se as an internal standard; and (3) analysis of the urine NIST SRM 2670, using standard addition and internal standardization, gave As and Se concentrations of 500 +- 130 ng/ml and 410 +- 80 ng ml , respectively, as compared to certified values of 480 +- 100 ng ml and 460 +- 30 ng ml for As and Se, respectively. Finally, the current limitations of He ICP for practical spectrometric analysis of aqueous samples are briefly contrasted with spectrometric techniques involving microwave induced plasmas and Ar ICP.

The certification of cocaine and benzoylecgonine in a human urine standard reference material.

The concentrations of cocaine and benzoylecgonine (BE) in Standard Reference Material (SRM) 1508, cocaine and metabolites in freeze-dried human urine, were determined at the National Institute of Standards and Technology (NIST, formerly NBS) by two independent methods. For cocaine, one method was based on gas chromatography/mass spectrometry (GC/MS); the other was based on high-performance liquid chromatography (HPLC). For BE, one method was based on GC/MS; the other was based on flow injection analysis/thermospray mass spectrometry (FIA/MS). The results for each pair of methods were statistically evaluated. Concentrations were determined in the SRM for three levels of cocaine and three levels of benzoylecgonine. Methylecgonine, although present in the material, was not determined. For cocaine, the concentrations were 90, 263, and 429 ng/mL of human urine. For BE, the concentrations were 103, 259, and 510 ng/mL of human urine.

Purge and trap flame photometric gas chromatography technique for the speciation of trace organotin and organosulfur compounds in a human urine standard reference material (SRM).

Ultratrace levels of organotin species and an organosulfur compound were detected in a National Bureau of Standards (NBS) human urine Standard Reference Material, SRM 2670, and a previously certified urine SRM 2672, using a purge and trap system coupled to a gas chromatograph equipped with a flame photometric detector. samples of the SRM were treated with sodium borohydride to form volatile tin hydrides. Species detected included dimethyltin (1.04 ng/ml), butyltin (0.03 ng/ml), and dimethyl-disulfide (2.73 ng/ml) in the new stock of freeze dried human urine SRM 2670 being prepared for issue by NBS and methyltin (1.0 ng/ml), butyltin (1.5 ng/ml), and inorganic tin (28.1 ng/ml) in the old stock of SRM 2672. This analytical technique should have useful applications in studies that are needed to develop a toxicological data base and monitoring programs for human organotin exposure.