High performance graphite furnace tube for determination of lead in blood

Importance of the topic

Exposure to lead poses significant health risks, especially in children. Accurate determination of blood lead levels is essential for clinical diagnostics, environmental monitoring, and public health decision making. Graphite furnace atomic absorption spectroscopy (GF-AAS) remains a cornerstone technique for trace metal analysis due to its sensitivity and precision, but continuous improvements in tube design and platform technology are required to overcome sample matrix challenges and to extend tube lifetime and analytical performance.

Study objectives and overview

This application note evaluates a novel high-performance graphite furnace tube—Agilent’s Omega Platform Tube—for the determination of lead in blood using an Agilent 280Z AA spectrometer with Zeeman background correction. The study aims to compare sensitivity, detection limits, precision, and robustness of the Omega Platform Tube against previous designs when applied to a complex biological matrix.

Methodology

Sample preparation and calibration were conducted with non-ionic surfactant/phosphate matrix modifiers to lyse cells, stabilize lead, and permit higher ashing temperatures. Calibration standards and matrix spikes were prepared daily from certified lead solutions and Lyphochek whole blood controls. Key steps included:

1. Dilution of porcine blood samples and controls with surfactant/phosphate solution.
2. Preparation of five calibration levels (0.0483 to 0.3382 µmol/L Pb) and blank.
3. Use of automated sample dispensing (Agilent PSD-120) with optimized rinse procedures to prevent carry-over.
4. Application of a 13-step furnace temperature program under high-purity argon to achieve efficient drying, ashing, atomization, and cleaning.

Used instrumentation

• Agilent 280Z AA spectrometer with Zeeman background correction and UltrAA hollow cathode lamp.
• GTA-120 graphite tube atomizer fitted with the Omega Platform Tube.
• PSD-120 programmable sample dispenser for automated aliquoting and standard preparation.
• Tube-CAM furnace viewing camera for real-time monitoring of tube conditions and capillary positioning.

Results and discussion

The Omega Platform Tube delivered excellent performance for lead in blood. Calibration curves exhibited a correlation coefficient (R2) of 0.9992. Spike recoveries were 100% for a 0.14 µmol/L addition, and certified reference materials returned recoveries of 98% (0.41 µmol/L) and 105% (2.50 µmol/L). Tube-CAM images confirmed minimal carbon buildup after repeated analyses, and no sample carry-over was detected. The optimized temperature profile yielded high signal-to-noise ratios and reproducible peak areas across replicates.

Benefits and practical applications

• Enhanced sensitivity and lower detection limits for blood lead analysis.
• Improved tube lifetime and reduced memory effects thanks to the Omega Platform design.
• Robust performance with complex biological matrices using Zeeman background correction.
• Automated workflows enabled by PSD-120 reduce manual handling and increase throughput.

Future trends and opportunities

Advances in platform tube coatings and geometries may further extend tube life and analytical sensitivity. Integration of advanced background correction techniques and real-time imaging will support method development and troubleshooting. The Omega Platform Tube design principles can be adapted to other trace metal assays in environmental, clinical, and food safety testing.

Conclusion

The Agilent Omega Platform Tube combined with GF-AAS and Zeeman correction provides a reliable, sensitive, and precise method for determining lead in blood. Its robust performance in challenging matrices, automation compatibility, and extended tube lifetime make it a valuable tool for laboratories requiring high-throughput and high-confidence trace metal analysis.

References

1. Gerberding JL, et al. Preventing Lead Poisoning in Young Children, 5th Revision. Centers for Disease Control and Prevention; 2005.
2. Hinderberger EJ, Kaiser ML, Koirtyohann SR. Atomic Spectroscopy 1981;2(1):1–7.