|
|
|
|
| NIRE Annual Report | 
| 1998 |
Determination of Metal Elements in Very Small Amount of DustsAir Quality Measurement DivisionAtmospheric Environmental Protection Department |
|---|
Objectives
In recent years, the concentration of exhausted dusts became very low. So it becomes very difficult to analyze the composition of elements and to detect the elements in size fractionated dust. The order of weights of the samples is less than mg. Therefore, we tried to use SIMS which has high sensitivity and is able to analyze multielements simultaneously. But, inhomogeneity of sample prevents the determination of the elements. So for the aim of quantitative analysis of these samples by means of SIMS, two methods on the preparation of samples were examined. One is the use of the iron coprecipitation(IC) after being homogenized1) and the other is the use of dried droplet residues(DDR). We tried these two methods to actual samples.
Results
1) Iron coprecipitation(IC) method1)
The values of RSD of the secondary ion intensity at repetition (n=10) showed high precision with the values of 1.8%(Ti), 2.0%(V), 1.9%(Cr), and 1.9%(Mn). In the trial to actual samples, we analyzed the dust of a dust collector of sintering furnace in an iron mill. We used the value of chemical analysis of Fe as standard value. It is in good accord of the value of chemical analysis with the value of SIMS. (Table 1)
2) Microdroplet method
The RSD's of the secondary ion intensity at repetition (n=10) were very low with the values of 2.1%(Ti), 1.8%(V), 4.7%(Cr), 2.4%(Mn), 3.2%(Pb), and 2.4%(Mg). But, precision of this method is inferior to the method of coprecipitation.
3) Analysis of dust samplesSamples from three dust collectors (No.1,No.2,No.3) of a sintering furnace used in the iron industry were analyzed by two methods. The analytical result by the method of IC is shown in the Table 1, and by the method of DDR is shown in Table 2. The method of microdroplet is inferior on precision of quantitative analysis to the method of coprecipitation. However, this method can be adapted to the analysis of polyelements in the extremely small quantities of samples in dust in size fractionated dust.
It was cleared that both IC method and DDR method are facile to draw the calibration curves. Both methods can be adapted to quantitative analysis.
Selected Publications
1) Bunseki Kagaku.,42,473,1993
