使用同位素比率质谱法测定不同来源的（E）-肉桂酸甲酯的2H/1H和13C/12C同位素比率。

Determination of 2H/1H and 13C/12C isotope ratios of (E)-methyl cinnamate from different sources using isotope ratio mass spectrometry.

作者信息

Fink Kathrin, Richling Elke, Heckel Frank, Schreier Peter

机构信息

Lehrstuhl für Lebensmittelchemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.

出版信息

J Agric Food Chem. 2004 May 19;52(10):3065-8. doi: 10.1021/jf040018j.

DOI:10.1021/jf040018j

PMID:15137854

Abstract

For the authenticity assessment of (E)-methyl cinnamate from different origins, combustion/pyrolysis-isotope ratio mass spectrometry (C/P-IRMS) was used by an elemental analyzer (EA) and on-line capillary gas chromatography coupling (HRGC-C/P-IRMS). For that reason, (E)-methyl cinnamate self-prepared from synthetic, natural, and semisynthetic educts was analyzed in comparison to the commercial synthetic and natural ester. In addition, (E)-methyl cinnamate from basil extract and a number of commercial natural aromas was investigated. The data of self-synthesized synthetic (E)-methyl cinnamate, i.e., delta(13)C(V)(-)(PDB) = -33.8 per thousand and delta(2)H(V)(-)(SMOW) = +349 per thousand, corresponded with that found for the commercial synthetic samples (-29.5 to -31.4 per thousand and +328 to +360 per thousand for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively). The ester produced from natural educts by acid as well as Candida antarctica catalysis revealed delta(13)C(V)(-)(PDB) = -25.6 and -30.1 per thousand as well as delta(2)H(V)(-)(SMOW) = -162 and -169 per thousand, respectively. Acid-catalyzed semisynthetic products differed in their delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) values depending on the origin of their educts. For the ester from synthetic methanol and natural cinnamic acid, -27.3 and -126 per thousand were determined for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively, whereas for the ester produced from natural methanol and synthetic acid delta(13)C(V)(-)(PDB) = -30.6 per thousand and delta(2)H(V)(-)(SMOW) = +287 per thousand were found. Basil extract showed -28.9 and -133 per thousand for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively. Commercial aromas declared to be natural revealed delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data ranging from -25.7 to -28.5 per thousand as well as -85 to -191 per thousand, respectively, indicating, in part, incorrect declaration.

摘要

为了对不同来源的肉桂酸甲酯（E）进行真伪评估，采用了燃烧/热解-同位素比率质谱法（C/P-IRMS），通过元素分析仪（EA）和在线毛细管气相色谱联用（HRGC-C/P-IRMS）。因此，将由合成、天然和半合成原料自制的肉桂酸甲酯（E）与市售合成酯和天然酯进行了比较分析。此外，还研究了罗勒提取物中的肉桂酸甲酯（E）以及一些市售天然香料。自制合成肉桂酸甲酯（E）的数据，即δ(13)C(V)(-)(PDB)=-33.8‰和δ(2)H(V)(-)(SMOW)=+349‰，与市售合成样品的数据相对应（δ(13)C(V)(-)(PDB)为-29.5至-31.4‰，δ(2)H(V)(-)(SMOW)为+328至+360‰）。由天然原料经酸催化以及南极假丝酵母催化生成的酯，其δ(13)C(V)(-)(PDB)分别为-25.6‰和-30.1‰，δ(2)H(V)(-)(SMOW)分别为-162‰和-169‰。酸催化的半合成产品，其δ(13)C(V)(-)(PDB)和δ(2)H(V)(-)(SMOW)值因原料来源而异。对于由合成甲醇和天然肉桂酸生成的酯，δ(13)C(V)(-)(PDB)和δ(2)H(V)(-)(SMOW)分别测定为-27.3‰和-126‰，而对于由天然甲醇和合成酸生成的酯，δ(13)C(V)(-)(PDB)=-30.6‰，δ(2)H(V)(-)(SMOW)=+287‰。罗勒提取物的δ(13)C(V)(-)(PDB)和δ(2)H(V)(-)(SMOW)分别为-28.9‰和-133‰。宣称是天然的市售香料，其δ(13)C(V)(-)(PDB)和δ(2)H(V)(-)(SMOW)数据分别为-25.7至-28.5‰以及-85至-191‰，部分表明了申报有误。