CCQM-K95.1 Low-polarity analytes in a botanical matrix: polycyclic aromatic hydrocarbons (PAHs) in tea
Authors: Duewer David L , Murray Jacolin A , Wood Laura J , Wise Stephen A , Sander Lane C , Lippa Katrice , Hein Sebastian , Koch Matthias , Philipp Rosemarie , Werneburg Martina , Hackenberg Rudolf , Polzer Joachim , Avila Marco A , Serrano Victor , Kakoulides Elias , Alexopoulos Charalampos , Giannikopoulou Panagiota , Gui Ee Mei , Lu Ting , Teo Tang Lin , Hua Tang , Dazhou Chen , Chunxin Li , Changjun Ye , Hongmei Li , Nammoonnoy Jintana , Quinn Laura , Swiegelaar Caitlin , Fernandes-Whaley Maria , Gören Ahmet Ceyhan , Gökçen Taner 
Published: November 2018

Extraction, chromatographic separation, and quantification of low-concentration organic compounds in complex matrices are core challenges for reference material producers and providers of calibration services. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2014 the Organic Analysis Working Group (OAWG) initiated CCQM-K95.1 “Low-Polarity Analytes in a Botanical Matrix: Polycyclic Aromatic Hydrocarbons (PAHs) in Tea”. This was a follow-on comparison from CCQM-K95 which was completed in 2014.
The polycyclic aromatic hydrocarbons (PAHs) benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) are considered priority pollutants by U.S. Environmental Protection Agency and are regulated contaminants in food, pose chromatographic separation challenges, and for which exist well-characterized measurement procedures and standard materials. BaA and BaP in a smoked tea were therefore selected as representative target measurands for CCQM-K95.1. Ten NMIs participated in CCQM-K95.1. The consensus summary mass fractions for the two PAHs are in the range of (50 to 70) ng/g with relative standard deviations of (6 to 10) %.
Successful participation in CCQM K95.1 demonstrates the following measurement capabilities in determining mass fraction of organic compounds, with molar mass of 100 g/mol to 500 g/mol and having polarity pKow −2, in a botanical matrix ranging in mass fraction from 10 ng/g to 1000 ng/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, (3) extraction of analytes of interest from the matrix, (4) cleanup and separation of analytes of interest from interfering matrix or extract components, and (5) separation and quantification using gas chromatography or liquid chromatography.
KEY WORDS FOR SEARCH
benz[a]anthracene (BaA), benzo[a]pyrene (BaP), gas chromatography(GC), isotope dilution (ID), liquid chromatography (LC), mass spectrometry (MS), polycyclic aromatic hydrocarbon (PAH), yerba mate tea

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The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).