Culomtery is based on the exact analytical chemical reaction and recently developed techniques, but not so refered to a simple measurement of physical quantities as other instrumental analytical methods. Recently the controlled potential coulometry developed to be applied to analytical method for determination of actinide elements (U, Pu, etc.) and rare elements (Np, Ir, Ru, In, Tl, Tc, etc.) mostly in buffered tripolyphosphate medium, while the organic substances (olefin, carboxlic acids, aromatic amines, phenols, etc.) were successively determined by electrogenerated bromine according to coulometric titration method. Especially, the unstable reagents such as Cr(II) or Mn(III) are capable of being electrogenerated from Cr(III) by reduction or from Mn(II) by oxydation and are respectively employed in coulometric reduction or oxydation. I-Q (current-coulomb) recording coulometer is very available in all the coulometric methods, because the coulomb can be easily calculated by the intersection of extrapolated I-Q line to the electrolysis current axis. Another new technique in the coulometry is a coulogram method which uses a scanning coulometer and records a coulomb-potential curve of a reversible process under nearly equilibrium conditions. The circuit is shown in Fig. 1 and features a novel system for producing a scan rate that is an inverse function of electrolysis current. Application of the method was given to direct determination of Pu in irradiated nuclear fuel. Constant current potential limit coulometry (C.C.P.L.) has the simplicity of constant current method as well as the versatility of controlled potential method. In this methed the potential approaches to preset potential during the constant current electrolysis and then the electrolysis current is set forward low constant current. The block diagram is shown in Fig. 2. Operational amplifier was recently used in coulometer and potentiostat of coulometric apparatus, resulting the coulometry to develope as an exact and reliable method of analysis. The example is given in Fig. 3. For the purpose of increasing the sensitivity and precision, differential coulometric titration method is considered to be a versatile method of analysis. Moreover, high speed controlled potential coulometry which uses a large electrode area against solution volume and the stirring by ultrasonic device or nitrogen gas bubble is one of an interesting method for practical analysis. The trend of coulometer for coulometry is to use the integrating motor for measurement of coulomb. The coulometer using relaxation oscillator has not yet proved to show a linear relationship between electrolysis current and revoluton of the motor. Recently, voltage-to-frequency convertor type coulometer is available for rapid constant potential coulometry. The pulse which is proportional to the electrolysis current is read by electron counter. Pulse coulometry uses the constant pulse for electrolysis current and the coulomb cousumed for the electrolysis can be read by means of electron counter. The pulse generating circuit is shown in Fig. 4. The coulometric titration can be carried out in non-aqueous solution such as isopropanol. Recently, a coulometric acidimetry was proposed for determination of organic weak acids. The coulometric titration was also tried in fused medium of LiCl-RCl mixed salts. This coulometry has advantage in high sensitivity over polarography or chrono-potentiometry in fused salts medium. The constant potential coulometry with anodic stripping method to be available for determination of Zn Cd, or Ni fused salts bath. Stripping coulometry was applied to determination of organic compounds by means of using an acetyleneblack electrode which adsorbs or contains the organic compounds inn the apparatus shown in Fig.5 and strips coulometrically. Generally, the radical titration can not be available by conventional titration technique, but available by coulometric technique. Biphenyl in

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In 1958, D.L. Love reported the “New techique in radiochemical determinations using polarographic method”, in which he used a polarographic cell shown in Fig. 1. Mercury is placed in the side arm containing the platinum electrode and the cell with the stopcock closed is filled with carbon tetrachloride to just below the mercury pool electrode. The active solution is placed above the carbon tetrachloride and in contact with the electrode. The D.M.E. is placed in the solution. The purpose of the large volume of carbon tetrachloride in the other compartment is to keep the solution-carbon tetrachlo-ride interface at a constant height when the drops fall through the solution and are removed by turning the stopcock. The radiometric polarography thus introduced was improved and developed by Love-Greendale, the authors, Chmelar et al., and several other investigators. The design of the electrolytic cell depends on the nature of solvent in which mercury drops are collected. Several kinds of cells are shown in Fig. 1, 4, 5, and 6. The methods of cleaning the mercury collected, the minimum concentrations of several nuclides and the precision of the radiometric polarography are discussed. The derivation of the equation of radioactivity-potential curve is carried out and the method of calibration is stated. Five examples reported by Love and Love-Greendale are abstracted; 1. ⁶⁰Co, 2. ⁹⁵Zr-⁹⁵Nb, 3. ¹⁰⁶Ru-¹⁰⁶Rh, 4. ^99mTc, 5. ¹¹³Sn-^113mIn. Experiments on ⁶⁵Zn and ¹⁹⁸Tl reported by the authors are introduced. It is pos-sible to take quantitative radiometric polarogram on 2.4×10^-11M-¹⁹⁸Tl. Schaap Wild-man worked on 10^-16M-²⁰⁴ Tl. Coulometry has intimate connection with the radiometric polarography. Two examples, i.e. on ⁶⁰Co and radioactive silver are abstracted. On two systems of polarographic wave of catalytic nature, i.e. Th⁴⁺-NO₃ and ZrO⁺⁺-BrO₃⁺ systems, had been investigated by the authors. In both cases no catalyser metal does not deposit on mercury electrode at the potentials at which the catalytic waves appear. Radiometric polarography on ⁶⁰Co concerning the Brdicka catalytic wave of hydrogen is reviewed. The authors recognized an analogous formed cpm/t-E pattern of histidine to the ordinary polarogram, but both of the grams disappear on adding gelatin. Catalytic waves due to serum, cystine with gelatin or mecthylcellulose have cpm/t-E patterns which shows single wave of cobalt only and no catalytic peak form. Chmelar, Bfezina and Kalous29 worked out on the “radiopolarography” on ⁶⁰Co concerning the Brdicka reaction, and recognized the cpm - E patterns on cobalt wave and catalytic hydrogen peak form wave. On addition of sufficient gelatin, the cpm/t-E pattern is reduced to the same pattern as wave of cobalt, though there is no effect on the ordinary polarogram. The authors seem that the reason of cpm/t-E pattern corresponding catalytic wave of hydrogen is reduced to the induced reduction of ⁶⁰Co as can be seen at the potential of reduction of supporting electrolyte in many examples and as ⁹⁵Zn deposition at cadmium and cobalt waves. Colléns technique of isotope separation of ⁶Li and ⁷Li is introduced. The method, like Love's radiometric polarography, makes use of carbon tetrachloride to cathodic mercury, which is streaming through the electrolytic solution of lithium chloride.

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　[Co(NO₂)₂(NH₃)_m]^(3-n)+型(n+m=6,n=0,1,2,3)錯体の第1段還元波(1電子還元)について電極反応速度パラメーターの解析を行ない。見かけのE_½R_f^a,ΔH_f^a≠は錯体の分光化学系列順位と一致した傾向を示すが,Frumkin補正値は一致しないことを認めた.これについて補正に用いたΔψ値がNO^2-の特異吸着.錯体双極子と電極との相互作用,錯体のイオン対生成など多くの因子を考慮して評価されねばならないであろうことが指摘される。

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　本分析法はク形波ポープログラフ法によりナフサ留分中の極微量メルカプタンおよび遊離イオウを同時定量することを目的とする.メルカプタンのポーラログラフ法による定量法は1958年のハンブルスキム法による定性的な検討以外,今までのところほとんど行なわれていない.また現在のASTM法,その他の方法では,とうていこのような物質の極微量(数ppm)分析は不可能である.一方,石油留分中の遊離イオウの定量法については,1950年にHallが,ガソリン留分にポーラログラフ法を適用して以来,現在までに数種の改良法が発表されている.　(1)装置:柳本製,交直両用ポーラログラフPA102型および高感度装置PM1型を使用した.電解セルにはFig.1に示すごとくH型セルに2000μFコンデンサーを接続し,液絡部の抵抗を出来るだけ少さくして実験を行なった。　(2)基礎液:最適条件としてピリジン,メタノール,酢酸ナトリウムの混合溶液を得た.そこで試料の溶解度,誘電率,その他種々条件を考慮して,その割合を検討した結果,ピリジン14vol%,メタノール86vol%,0.4M酢酸ナトリウムが最適と認めた。　(3)ポーラログラム:メルカプタンについては十数種類の化合物について検討した結果,本分析法の基礎液によると,頂点電位は-0.48 - -0.55V.vs.SCEを示すことがわかった.その一例として,20ppm.のn-Propyl mercaptanが本基礎液中であたえるポーラログラムをFig.2に示す。遊離イオウは.二段波を示し,第1波は-0.52V,第2波は-0.72V.vs.SCEに頂点電位を示す.しかるに,遊離イオウの第1波とメルカプタン化合物の波が重なってくる.故に定量時において,遊離イオウが共存している場合には,遊離イオウの第2波の波高から検量線により第1波の波高を求め,メルカプタンの真の波高を求めねばならない.　(4)温度の影響:メルカプタン化合物については.Fig.3に示す如く,温度変化によって,ポーラログラムは変化する.この現象は滴下水銀電極上での吸着現象によるものではないかと考えられる.波高は作図の仕方によって異なるが,Fig.3の(A)法によると波高に変化なく,(B)法によれば温度に比例して波高は高くなる。(Fig.4参照)この場合の温度係数は19.6%/degreeであった。また遊離イオウについて,10-35 ℃の範囲内で検討した結果,Fig.5に示すごとく,第1波は温度の影響を受けないが,第2波は温度上昇とともに波高は増加する。　(5)共存物質の影響:ナフサ留分中で遊離イオウとメルカプタン以外のイオウ化合物として一応沸点範囲から考えて,H₂S,Disulfideなどが考えられる。このうちH2Sは-0.67V.vs.SGEにポーラログラムを示し,遊離イオウのポーラログラムに影響をおよぼす。　したがって,H₂Sは硫酸カドミウム処理により除去する。次にDsiulfideであるが,これは本条件においてポーラログラムを示さない。　以上の各条件により,分析した結果,分析精度はTablelに示したとおりとなり,定量下限は,おのおの1ppmで,この時の相対誤差はメルカプタンについては10.3%,遊離イオウは4.0%となる.

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シュウ酸塩を含む中性媒質(pH=6.9)中で等濃度のFMNおよびFe³⁺が共存する系のポーラログラムを記録すると,Fe³⁺-FMN錯塩→Fe³⁺+FMNなる解離反応により生じる遊離のFe³⁺の還元によるkinetic currentが現われる,ポーラログラフ的挙動から,上記反応系は平衝状態では左にかたよっていると考えられ,従ってFe³⁺の濃度をFMNに比して大過剰に共存させれば,上記反応系においてFMNは事実上すべてFe³⁺-FMN錯塩として存在するであろう.著者は前報の結果を応用し,クロノポテンシォメトリーによりFe³⁺イオン2個がFMN分子1個と結合することおよびFc²⁺とLeuc-FMNの結合は上記の酸化系程安定ではないと考えられる結果を得た.

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