反応ガスクロマトグラフィーを用いる国際単位系にトレーサブルな有機標準物質特性値の新規決定法

摘要

トレーサビリティを確保し不確かさ力M寸与された標準物質を開発するには，多くの時間と費用を必要とする.国際単位系（SI)にトレーサブルな標準物質の開発を簡易に行うことを目的として，反応による物質変換の技術を用いる研究を行い，新たな装置とその校正方法を開発した.ガスクロマトグラフ（GC)のカラム出口と水素炎イオン化検出器（FID)の間に酸化反応部と還元反応部を直列に組み込んだ装置では，優れた結果を得ることができた.この装置は，導入した試料成分をカラムで分離後，二酸化炭素に酸化し，直後にメタンへ還元しFIDで検出する.数種類のSIトレーサブルな標準物質を混合調製して本装置で測定し.メタン換算濃度とピーク面積値から関係線を求め直線となることで，反応系の反応効率を検証するとともに，装置の校正を行う.この関係線を用いて標準物質と異なる成分を含んだ試料を本装置で測定し，分離した成分すベての定量を行う.この新たな値付け法は，SIトレーサブルな標準物質の開発がより容易に行える画期的な方法である.%In this article, novel methods based on reaction gas chromatography are proposed to give SI-traceable characteristic values to compounds of interest in an organic standard material. In order to the assure reliability of an analytical value, its traceability is indispensable. Usually, in that case, standard materials whose characteristic values have their own uncertainties are needed to prepare the calibration curve. It is, however, difficult to obtain such standard materials. To prepare such a standard material, it costs a lot of money, and is time consuming. Therefore, a limited number of standard materials are available, and they are expensive. A study was carried out in order to prepare SI-traceable standard materials more simply. The systems that connected one or two parts using a technique for chemical conversion by reactions between a column and a detector were developed. Especially, the system that connected an oxidizing part and a reducing part in series between the column and the flame ionization detector (FID) showed excellent results. In this system, components to be evaluated were separated by the column, changed to carbon dioxide by oxidation, then reduced to methane, and detected with FID as methane. Both reaction efficiencies in the two reaction parts, oxidation to carbon dioxide and reduction to methane, were proved to be 100 %. The proposed method was validated using SI-traceable standard materials. Verification of the reaction efficiencies of the two reaction parts were established using Sl-txaceable standard materials, too. In this verification, the relation between the atomic concentration of carbon measured as methane and the chromatographic peak area, namely the linear regression was, obtained. At first the system was calibrated using SI-traceable standard materials that did not contain ethane; then, an ethane standard material whose characteristic value was determined by gravimetry was measured. The obtained value was SI-txaceable. This value and the characteristic value were in agreement with each other. The proposed method can be applied to organic compounds that consist of three elements: carbon, hydrogen, and oxygen. SI-traceable values of the compounds of interest in the organic standard materials can be obtained without each target compounds' standard materials by this method.