The high speed frequency modulation of a 460 GHz Gyrotron FU CW GVI (the official name in Osaka University is Gyrotron FU CW GO-I) was achieved by modulation of acceleration voltage of beam electrons. The modulation speed f m can be increased up to 10 kHz without decreasing the modulation amplitude δf of frequency. δf was increased almost linearly with the modulation amplitude of acceleration voltage δV a . At the δV a =1kV, δf=53 MHz in the case of f m <;10 kHz. The frequency modulation was observed as both the variation of the IF frequency in the heterodyne detection system measured by an oscilloscope and the width of frequency spectrum measured on a frequency spectrum analyzer. Both results well agree reasonably. The experiment was performed successfully for both a sinusoidal wave and a triangle-wave modulations. By using the frequency modulation, we have a possibility to compensate the decreasing of the enhancement factor in high frequency DNP-NMR spectroscopy for example, 700 MHz. In addition, high speed frequency modulation is useful for frequency stabilization by PID control of acceleration voltage by feeding back of fluctuation of the frequency. The frequency stabilization in long time is also important for application of DNP-NMR spectroscopy to analysis of complicated protein molecules.

Two demountable gyrotrons with internal mode converters were developded as sub-THz radiation sources for 700 MHz DNP (Dynamic Nuclear Polarization) enhanced NMR spectroscopy. Experimental study on the DNP-NMR spectroscopy will be carried out in Osaka University, Institute for Protein Research, as a collaboration with FIR UF. Both gyrotrons operate near 460 GHz and the output CW power measured at the end of transmission system made by circular waveguides is typically 20 to 30 watts. One of them named Gyrotron FU CW GVI (we are using “Gyrotron FU CW GO-1” as an official name in Osaka University) is designed to have a special function of high speed frequency modulation δf within 100 MHz band. This will expand excitable band width of ESR and increase the number of electron spins contributing to DNP. The other gyrotron, Gyrotron FU CW GVIA (“Gyrotron FU CW GO-II”) has a function of frequency tunability Δf in the range of wider than 1.5 GHz, which is achieved in steady state by changing magnetic field intensity. This function should be used for adjusting the output frequency at the optimal value to achieve the highest enhancement factor of DNP.

多種類の食品中の種々の許可及び不許可タール色素及び天然色素の統一的かつ系統的な分析法の確立を目的として,液体陰イオン交換樹脂アンバーライトLA-2を用いる液・液分配法を検討した.試料中の色素をアンモニアアルカリ性下1-ブタノールで抽出し,次いで酢酸酸性下5%LA-2含有1-ブタノールで抽出した.抽出液を合わせ,濃縮し,ヘキサンを加えた後,アンモニア水,次いで酢酸で抽出することにより,色素を油溶性,塩基性,酸性色素に系統的に分画した.各分画は簡単な後処理をした後,薄層及びペーパークロマトグラフィーで定性試験を,高速液体クロマトグラフィーで定量試験を行った.食品からの添加回収率は一部の色素を除き80%以上と良好であった.

食品中の種々の合成及び天然着色料の統一的かつ系統的な分析法として著者らが確立したセライトカラム法(C・C法)及び液・液分配法(L・L法)の比較検討を行った.既知量の着色料を添加し調製した試料を,未知検体として6機関に配布し,C・C法とL・L法で分析し,両法での回収率と測定値の標準偏差を求め比較した.各機関の回収率はよく一致した.合成着色料では全体的にC・C法に比し L・L 法の結果がわずかに高く,蒸しかまぼこ以外は80%以上となった.天然着色料では逆にC・C 法の回収率が高く,(75～95)%と良好であった.約40種の着色料含有の市販食品について,両法により使用されている着色料の同定及び定量を行い,結果を同様に比較した.同定された色素は両法で良く一致し,定量値は,合成着色料では両法ともほぼ一致し,天然着色料ではC・C法の測定値がいずれも少し高くなった.これらの結果から,食品中の着色料の分析法として,合成着色料の場合はL・L法が,天然着色料の場合はC・C法が優れていると言える.