リン酸アルキルアンモニウムを添加した移動相を用いる逆相高速液体クロマトグラフィーによるヨウ化物イオン及びヨウ素化チロニン類の同時分析

摘要

Volatile sulfuric and nitrogenous compounds are well- known odor compounds derived from the breath. Recently, some short-chain fatty acids have been suggested to be related to oral mal-odor caused by certain oral diseases. Details of the mechanisms of oral malodor, however, have not been well understood, partly because of little content of such short-chain fatty acids in the breath and of the difficulty to collect sufficient amounts of them for analysis. To solve this problem, we have developed a new method, where the needle-type solid-phase micro-extraction technique and gas-chromatography mass spectrometry for collecting and for determining those fatty acids were utilized, respectively. As a result, isovaleric acid, butanoic acid and 2-methyl butanoic acid were detected in mouth air, and we determined the concentration of them under well-controlled conditions. The concentrations of isovaleric acid in saliva were also determined for a comparison, and found to be in accordance with those in the mouth air. (r = 0.4953, p < 0.0001). Therefore, such short-chain fatty acids in mouth air may originate from saliva. There was a correlation between the amount of the isovaleric acid and the strength of the oral malodor assessed by organoleptic tests (r = 0.3426, p < 0.001). Those results showed that the short-chain fatty acids could cause the oral malodor.%イオン対（IP）試薬としてリン酸アルキルアンモニウムを添加した移動相を用いる紫外吸光（UV）検出／逆相高速液体クロマトグラフィー（HPLC）で，ヨウ化物イオン（I~-）及びヨウ素化チロニン類を同時分析する方法を検討した．本研究では，カラムにSunrise C18を用い，移動相の諸条件（pH,IP試薬の種類など）がI~-及びヨウ素チロニン類の保持に及ぼす影響を系統的に調べた．その結果から，分離に至適な移動相として5mMリン酸トリプチルアンモニウム（pH3.0）-アセトニトリル（64:36,v/v）を選定し，これらのヨウ素化合物を分析した．いずれの化合物も良好な定量性を示した．この分析法を市販の甲状腺ホルモン製剤に含まれるI~-及びヨウ素化チロニン類の同時分析に応用した．