Final report on CCQM-K38: Determination of PAHs in solution

Solutions of known mass fraction of organic analytes of interest are typically used to calibrate the measurement processes used in the determination of these analytes. Appropriate value assignments and uncertainty calculations for these calibration solutions are critical. For the Mutual Recognition Arrangement (MRA) developed by the CIPM, there are numerous Calibration and Measurement Capability Claims (CMCs) published in Category 3 Organic Solutions in the CIPM MRA Appendix C. Additional CMCs in this category are being proposed and reviewed. Evidence of successful participation in formal, relevant international comparisons is needed to support these claims. A CCQM pilot study conducted in 2004 was comprised of three parts: CCQM-P31a Organic Solution—Polycyclic Aromatic Hydrocarbons (PAHs), CCQM-P31b Organic Solution—Polychlorinated Biphenyl (PCB) Congeners, and CCQM-P31c Organic Solution—Chlorinated Pesticides. The results from the CCQM-P31a study are summarized below for the PAHs. After review of the P31a results at the April 2004 Organic Analytical Working Group (OAWG) meeting (Sevres 2004) and the October 2004 OAWG meeting (Beijing 2004), it was decided to proceed with a key comparison study for PAHs in solution (CCQM-K38) with a concurrent second pilot study for the PAHs in solution (CCQM-P31a.1). CCQM-K38 was conducted during the same time period as a PAHs in soil pilot study (CCQM-P69) coordinated by CENAM and BAM. This Key Comparison study demonstrated a high level of equivalence in capabilities of the participating NMIs to successfully identify and measure five PAHs (phenanthrene, fluoranthene, benz[a]anthracene, benzo[a]pyrene, and benzo[ghi]perylene) in a solution using GC/MS-based methods. The PAHs measured in CCQM-K38 were selected to be representative of PAHs typically used as calibrants in the determination of the PAHs found in environmental samples and to provide the typical analytical measurement challenges encountered in the value-assignment of these PAH calibration solutions, such as volatility losses and resolution from potential interferences and other PAHs present as components in the solution during chromatographic separation. The abilities demonstrated by the laboratories that provided comparable measurements for all five PAHs in this Key Comparison should be indicative of their ability to provide reference measurements for a suite of PAHs in solutions when present at levels greater than 3 µg/g provided the laboratory demonstrates an acceptable degree of separation of the PAHs in the specific solution being analyzed. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).