Chuzo Iida

Small spray chamber for inductively coupled plasma atomic emission spectrometry and its evaluation by a digital signal sampling technique

The practical performance of a small single-barrel spray chamber was evaluated with special regard to the response time attained for the discrete nebulisation technique in inductively coupled plasma atomic emission spectrometry. The precision, sensitivity and response times obtained with chambers of various sizes were compared by digital signal sampling and processing using a personal computer. For a precise comparison, two parallel chamber systems, each having an individual chamber, cross-flow nebuliser and drain trap, were switched alternately with a 3-way valve with the plasma on. One system was equipped with the chamber being investigated and the other with a fixed chamber as a reference. The small chamber, 1.8 cm i.d. and 5 cm in length, was recommended for discrete nebulisation, because of its faster response and better precision compared with a chamber of a size normally available commercially. The small chamber also showed good performance characteristics with continuous nebulisation.

Determination of copper by flame atomic absorption spectrometry using discrete nebulisation of a carbon tetrachloride extract

Copper extracted into carbon tetrachloride as a dithizonate was determined by flame atomic absorption spectrometry with discrete nebulisation and without deuterium background correction. Injection of the organic extract gave an interesting signal profile, owing to the decrease in the flame temperature. Injection volumes of 35–45 µl of the organic extract gave the highest, most constant and reproducible signals. For the same copper concentration, the signal intensity obtained by injecting 40 µl of the extract was about 1.6 times larger than that obtained both by continuous nebulisation of the extract and by injection of 100 µl of aqueous solution. The detection limit obtained by injecting 40 µl of the extract was 49 p.p.b. or 2.0 ng [signal to noise ratio (S/N)= 2]. The method was successfully applied to the determination of copper in a certified reference material from the National Institute for Environmental Studies (NIES-CRM No. 9, Sargasso), and the results agreed well with the certified value.

Recycling nebulisation system with exchangeable spray chamber for inductively coupled plasma atomic emission spectrometry

A recycling nebulisation system with a small exchangeable spray chamber was developed for inductively coupled plasma atomic emission spectrometry, allowing rapid exchange of samples without extinguishing the plasma. The exchange of the chamber required only 3 min with a memory effect of less than 0.01%. The proposed system allowed continuous nebulisation for 30 min with 2 ml of sample, but a gradual increase in the signal was observed owing to the enrichment of determinants. This signal drift was almost cancelled out in sequential measurements, because the elements were measured in the same sequence for both samples and standards. The system was successfully applied to the analysis of some certified reference materials.

Discrete nebulisation in inductively coupled plasma atomic emission spectrometry of manganese

The inductively coupled plasma atomic emission spectrometer with discrete nebulisation gives a spike-like signal. The peak height of the signal is proportional to the metal concentration in a sample solution at a constant injection volume. The peak area, on the other hand, corresponds to the absolute amount of metal in the injection volume. Linear plots of peak area versus absolute amount, i.e., calibration graphs, are obtained by injecting (1) a constant volume of standard solutions of different concentrations and (2) different volumes of a standard solution of a constant concentration. The calibration graphs thus obtained are identical with each other. With these calibration methods, manganese was successfully determined in the standard biological material NIES-CRM No. 6 Mussel.

Effect of organic solvents on the flame atomic absorption spectrometry of copper using discrete nebulisation of mixed aqueous solutions

The relationships between the relative viscosity of mixed aqueous-organic solvents and signal height, signal area, aspiration time and the ratio of the signal area to the aspiration time have been investigated in the flame atomic absorption spectrometry of copper with discrete nebulisation of 100 µl of solution under constant flame conditions. The signal area and aspiration time increased with increasing viscosity, while the signal height varied irregularly with the viscosity and with the combination of solvents. The aqueous-organic solvents studied were the ethanol-water, acetone-water, propan-1-ol-water and butan-1-ol-water systems. For 43%m/m(50%V/V) aqueous ethanol and acetone solutions, i.e., at their maximum viscosities, the signal areas were ca. 2.3 and 1.9 times larger than that for the aqueous solutions alone, but the signal heights were 0.80 and 1.06 times larger, respectively. In the presence of 25%m/m ethanol, copper was determined in bovine liver by the signal area and absolute mass methods using 50-µl injection volumes, with good sensitivity and accuracy.

Application of absolute amount measurement in flame AAS; Extension of linear range of calibration curve.

原子吸光光度計の平均吸光値測定回路の一部変更と,自製の測定開始用オートトリガーインターフェイスにより,積分吸光値(シグナル全面積)を簡便迅速に測定できた.一定容量の溶液を断続的に噴霧する一滴法において,ピーク面積は注入した溶液中の目的元素の絶対量に比例することを応用し,試料溶液注入量とそれに対応する積分時間の増減のみにより,あらかじめ設定した検量線の適用濃度範囲を高低両濃度域に見掛け上約一けた拡張することを11元素について検討した.本法により標準植物試料(リョウブ)中のCu,Mg及びMnを定量し,良好な結果を得た.