Contaminants in organic geochemical analysis

2020/5/27 7:352021/5/28 7:22

フタル酸エステル類 Phthalates

o-フタル酸とアルコールのエステルで、熱可塑性樹脂の可塑剤としてよく用いられる。実験手順における混入を避け、バックグラウンドの汚染を低減するため、高純度の溶媒の使用、グラスウールやアルミホイルなどの材料の洗浄・ベーキングなどの対策を行うが，徹底的に対策をしても、実験室内でフタル酸エステル類の混入を完全に防止することは困難で、有機地球化学分析でもよく見掛ける典型的な汚染物質であるが、フタル酸エステル類そのものを分析対象としない場合には大きな問題にはならない。洗浄後にアルミホイルで包んだガラス器具も保管中に汚染される (Lopez-avila et al., 1990, J. Assoc. Off. Anal. Chem. 73 pp.709-720.)。

BAQCs, Fatty acid amides (Oleamides), butylated hydroxytoluene (BHT), octadecyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate (Irganox 1076, Ciba), Octabenzone, Parsol MCX

Identification of BAQCs:

Structure and distribution of branched aliphatic alkanes with quaternary carbon atoms in Cenomanian and Turonian black shales of Pasquia Hills (Saskatchewan, Canada)

Twelve pseudohomologous series of branched alkanes with one or two quaternary carbon atoms (BAQCs; C 14-C 33 range) are present in the extractable organic matter of Cenomanian and Turonian black shales of Pasquia Hills (Saskatchewan, Canada). Five of these pseudohomologous series are also observed in a Holocene sample from the Russian Arctic.

https://www.sciencedirect.com/science/article/abs/pii/S0146638004001743

Source interpretations (as contaminants):

Incorporation of organic contaminants into geochemical samples and an assessment of potential sources: Examples from Geoscience Australia marine survey S282

Organic geochemists are increasingly involved in multi-disciplinary collaborative studies but not often in the initial sample collection phase, so understanding the origin and source of contaminants derived from sample handling and containers is of vital importance as standard laboratory blanks cannot assess this contamination.

https://www.sciencedirect.com/science/article/abs/pii/S0146638007000198

Diisoprophyl naphthalenes (DIPNs)

synthetic/anthropogenic compounds used as plant growth regulators and in paper manufactory. base peak /mz 197, M+. m/z 212

Diisopropyl naphthalenes: Environmental contaminants of increasing importance for organic geochemical studies

Diisopropyl naphthalenes (DIPNs) have distinctive mass spectra, including a base peak at m/z 197 and M+. at m/z 212 and, on the apolar columns typically used in organic geochemical applications, are resolved into five main peaks, although there are ten possible isomers.

https://www.sciencedirect.com/science/article/abs/pii/S0146638010001567

中村英人 | Hideto Nakamura, Ph. D./📝Blog