Page 9 - Shimadzu PDA-7000

PDA Time-resolution Analysis

Shimadzu's unique PDA photometry is installed as standard to offer a variety of benefits for various analyses.
Reduced Effects of Sample Defects (cracks, pinholes) on Analysis Values
PDA Photometry (Pulse Distribution Analysis Photometry) (Patented)

Unlike conventional photometry that simply integrates the determine the percentage content. The internal standard monitoring method is applied to each To enhance reproducibility,
photocurrent obtained from discharges over a fixed time, the PDA permits speciation analysis and a variety of data discharge pulse to monitor the light intensity for internal statistical processing is used to
PDA method integrates the photocurrent obtained from each processing not possible with previous methods, which standard elements. If this value lies within the specified range, eliminate the data obtained
discharge pulse and analyzes each integral value as having an significantly increases the analysis accuracy for many elements. the light intensities obtained for the measured elements are when the spark is applied to a
individual significance. The optimal processing is then used to selected. defect resulting from sampling.
Time-resolution Analysis (Patented)

The discharge conditions to obtain the optimal measurement sensitivity differ for
Time-resolution Photometry
each spectral line.
I Monitoring with Internal Standards
The diagram at the right shows the current waveform for typical discharge
conditions. Some elements exhibit sensitivity in Area A, others in Area B. Analyzing
the elements separately in the individual areas dramatically enhances the sensitivity Spectral intensity
for trace elements. A B
The table below compares the Background Equivalent Concentration (BEC) values for T
a conventional method and the PDA-7000. Spectral intensity Spectral intensity( ) Spectral intensity( )
The lower the BEC value, the higher the sensitivity for trace elements.

Element C P S B
T 0
Conventional method(ppm) 160 150 100 80
Time Frequency of occurrence Internal standard elements Time (T) Measured elements Time (T)
PDA-7000(ppm) 80 75 50 40
: median value of internal standard elements ɺ : discriminator levels
Shorter Analysis Times (just over 10 seconds per analysis)
Combined discharge and PDA time-resolution photometry obtain results in just over ten seconds per analysis.

Data is Controllable for each Discharge, Allowing Photometric Values for
Abnormal Discharge Pulses to be Eliminated for Enhanced Accuracy Acid-soluble Speciation Analysis (Quantitation of Acid-soluble Aluminum)
Statistical processing based on the differences in light intensity between acid-soluble aluminum (sol-Al) and
Conventional photometry determines the overall integral value and then conducts statistical processing, thereby achieving
acid-insoluble aluminum (insol-Al) allows quantitation of acid-soluble aluminum in just 1 seconds.
of the light intensities. However, the PDA-7000 Series measurements that are unaffected by light intensities from
determines the frequency distribution of the light intensities abnormal discharges. Analyzed Sample Surface Principle of Speciation Analysis of Aluminum in Steel

Enhanced Accuraacy for Insoluble Elements that Readily Form Inclusions m : median value of analysis values
Insol AI
(Patented) Discharge including insol-Al N : total number of pulses sol AI
sol AI m× n Measured value
Discharge for sol-Al only n samples N
Achieves two or three times the reproducibility of conventional conventional method and the PDA-7000 for elements that
Shimadzu methods. readily form inclusions. insol AI Chemical Analysis of sol-Al
Frequency of occurrence
The table at the right compares reproducibility values for a n’ samples insol AI
Element Total Al S Pb B Ca n Measured value
Content (%) 0.037 0.022 0.005 0.0035 0.002 m× N
Reproducibility Conventional method 0.0025 0.0010 0.0010 0.00027 0.00045 Discharge spot m Spectral intensity Chemical Analysis of insol-Al
σ (%) PDA-7000 0.00045 0.0004 0.0002 0.00005 0.0001

PDA-7000 Series
8 Optical Emission Spectrometer 9