Practical Multi-Element Hollow Cathode Lamps for Atomic Absorption Spectrometry

Importance of the Topic

Multi element hollow cathode lamps offer a cost effective alternative to single element lamps in atomic absorption spectrometry enabling laboratories to reduce lamp inventory and operating expenses while maintaining analytical performance.

Goals and Overview of the Study

This study evaluates analytical figures of merit for selected elements using single and multi element lamps in flame atomic absorption spectrometry and compares their performance in the determination of metals in steel reference materials and real samples.

Methodology and Instrumentation

Samples of NIST 348a and BCS 336 reference steels and stainless and mild steel turnings were acid digested. Limits of detection and characteristic concentrations were determined using recommended operating currents. Concentrations in steel were measured using a nitrous oxide acetylene flame and fast sequential measurement mode.

Instrumental Setup

• SpectrAA 220FS atomic absorption spectrometer
• UltrAA lamp control module with boosted discharge option
• SPS 5 sample preparation system with diluter under automated software control
• N2O C2H2 flame for interference reduction

Main Results and Discussion

Multi element lamps achieved limits of detection and characteristic concentrations comparable to single element lamps. Emission intensities for some elements were reduced in combined lamps while others were enhanced. The boosted discharge design improved weaker analytical lines and reduced calibration curvature. Determinations of Co Mn Cr Mo and Ni in steel samples agreed within experimental error for both lamp types except for chromium which showed biased recoveries due to unmatched standard oxidation states.

Benefits and Practical Applications

Use of multi element lamps reduces lamp changeover time and inventory requirements and offers acceptable analytical performance for environmental and base metal analysis markets.

Future Trends and Opportunities

Further improvements in lamp design may extend the number of analyzable elements and enhance line intensities. Advances in boosted discharge and automated sampling are expected to broaden applications in industrial and environmental laboratories.

Conclusion

Well designed multi element hollow cathode lamps can match or exceed the performance of single element lamps in flame atomic absorption spectrometry and provide practical advantages in cost and workflow efficiency.

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