Sampling and Analytical Method for Alpha-Dicarbonyl Flavoring Compounds via Derivatization with o-Phenylenediamine and Analysis Using GC-NPD

Scientifica, May 2016

A novel methodology is described for the sampling and analysis of diacetyl, 2,3-pentanedione, 2,3-hexanedione, and 2,3-heptanedione. These analytes were collected on o-phenylenediamine-treated silica gel tubes and quantitatively recovered as the corresponding quinoxaline derivatives. After derivatization, the sorbent was desorbed in 3 mL of ethanol solvent and analyzed using gas chromatography/nitrogen-phosphorous detection (GC/NPD). The limits of detection (LOD) achieved for each analyte were determined to be in the range of 5–10 nanograms/sample. Evaluation of the on-tube derivatization procedure indicated that it is unaffected by humidities ranging from 20% to 80% and that the derivatization procedure was quantitative for analyte concentrations ranging from 0.1 μg to approximately 500 μg per sample. Storage stability studies indicated that the derivatives were stable for 30 days when stored at both ambient and refrigerated temperatures. Additional studies showed that the quinoxaline derivatives were quantitatively recovered when sampling up to a total volume of 72 L at a sampling rate of 50 cc/min. This method will be important to evaluate and monitor worker exposures in the food and flavoring industry. Samples can be collected over an 8-hour shift with up to 288 L total volume collected regardless of time, sampling rate, and/or the effects of humidity.

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Sampling and Analytical Method for Alpha-Dicarbonyl Flavoring Compounds via Derivatization with o-Phenylenediamine and Analysis Using GC-NPD

Sampling and Analytical Method for Alpha-Dicarbonyl Flavoring Compounds via Derivatization with o-Phenylenediamine and Analysis Using GC-NPD Stephanie M. Pendergrass1 and Jeffrey A. Cooper2 1National Institute for Occupational Safety and Health Centers for Disease Control and Prevention, Cincinnati, OH 45226, USA 2Bureau Veritas North America, Novi, MI 48375, USA Received 3 December 2015; Revised 25 February 2016; Accepted 4 April 2016 Academic Editor: Lidwien A. M. Smit Copyright © 2016 Stephanie M. Pendergrass and Jeffrey A. Cooper. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract A novel methodology is described for the sampling and analysis of diacetyl, 2,3-pentanedione, 2,3-hexanedione, and 2,3-heptanedione. These analytes were collected on o-phenylenediamine-treated silica gel tubes and quantitatively recovered as the corresponding quinoxaline derivatives. After derivatization, the sorbent was desorbed in 3 mL of ethanol solvent and analyzed using gas chromatography/nitrogen-phosphorous detection (GC/NPD). The limits of detection (LOD) achieved for each analyte were determined to be in the range of 5–10 nanograms/sample. Evaluation of the on-tube derivatization procedure indicated that it is unaffected by humidities ranging from 20% to 80% and that the derivatization procedure was quantitative for analyte concentrations ranging from 0.1 μg to approximately 500 μg per sample. Storage stability studies indicated that the derivatives were stable for 30 days when stored at both ambient and refrigerated temperatures. Additional studies showed that the quinoxaline derivatives were quantitatively recovered when sampling up to a total volume of 72 L at a sampling rate of 50 cc/min. This method will be important to evaluate and monitor worker exposures in the food and flavoring industry. Samples can be collected over an 8-hour shift with up to 288 L total volume collected regardless of time, sampling rate, and/or the effects of humidity. 1. Introduction In August 2000, the National Institute for Occupational Safety and Health (NIOSH) received a request for technical assistance (HETA # 00-0401) in an investigation of severe obstructive lung disease (bronchiolitis obliterans) in former workers of a microwave popcorn plant in Missouri [1]. NIOSH was asked to investigate a cluster of past and present employees experiencing severe respiratory symptoms after working in microwave popcorn processing facilities over a period of 3 months to 3 years [2]. A NIOSH medical and environmental survey at the plant in November 2000 demonstrated a strong exposure-response relationship between quantities of estimated cumulative exposure to diacetyl (a volatile butter flavoring chemical contaminating the air in the plant) and the frequency of airway obstruction on spirometry tests [1]. NIOSH method 2557, an air sampling method that uses Anasorb Carbon Molecular Sieve (CMS) sorbent tubes, was developed based on an urgent need for a method to collect and quantitate exposures and evaluate subsequent engineering control effectiveness [3]. This method was used extensively in the field for a number of years. Subsequent field evaluation work suggested a tendency of NIOSH method 2557 to underestimate the true concentration of diacetyl in air [4]. Additional laboratory studies identified that this method had reduced recoveries when samples were collected in moderate-to-high humidity environments. A NIOSH laboratory-based study and a chamber study with generated atmospheres established a correction method for previously collected data with the initial NIOSH method [5]. Concurrently, the Occupational Safety and Health Administration (OSHA) developed method PV2118 that collected diacetyl on a silica gel sorbent. While the method exhibited good storage stability for diacetyl, it had limitations in sampling time/volume because of the collection of water during air sampling [6]. In an effort to address the humidity concerns encountered by the NIOSH and OSHA methods, OSHA developed another method for the collection and analysis of diacetyl on specially dried silica gel tubes (2 tubes in series) [7]. By using the dried silica gel tubes in series, this OSHA method addressed migration issues encountered when a single silica gel tube was used. All of these methods utilize gas chromatography equipped with flame ionization detection (GC/FID) for sample analyses. In 2011, NIOSH published a draft criteria document titled “Criteria for a Recommended Standard: Exposure to Diacetyl and 2,3-Pentanedione” that contained a draft NIOSH Recommended Exposure Limit (REL) of 5 pbb, 8 hr-TWA for diacetyl [8]. The criteria document recommended OSHA method 1012 for sampling diacetyl exposures. This method utilizes o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride (PFBHA) to der (...truncated)


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Stephanie M. Pendergrass, Jeffrey A. Cooper. Sampling and Analytical Method for Alpha-Dicarbonyl Flavoring Compounds via Derivatization with o-Phenylenediamine and Analysis Using GC-NPD, Scientifica, 2016, 2016, DOI: 10.1155/2016/9059678