Determination of lead in whole blood by AA-1800 atomic absorption spectrometry - Master's thesis - Dissertation

Determination of Lead in Whole Blood by AA-1800 Atomic Absorption Spectrometry

This article introduces a method for determining lead levels in whole blood using the AA-1800 atomic absorption spectrometer. Lead is a multi-system and multi-affinity heavy metal poison that primarily affects the placenta and nervous system. Even small amounts of lead in the body can cause harm, especially to children, where high concentrations may lead to irreversible brain damage. Blood lead levels are a key indicator of recent exposure and are widely used in health assessments. The World Health Organization (WHO) has set a biological threshold of 100 µg/L for blood lead in children. Although no national standard exists yet, the Ministry of Health in China issued the WS/T174-1999 guideline, which recommends acid deproteinization followed by graphite furnace atomic absorption spectrometry. In this study, we adapted this method by using 10% (V/V) nitric acid to remove blood proteins, ensuring the sample is stable and less prone to splashing during analysis. The process involves two-step drying in the graphite furnace to prevent sample loss. We also tested the accuracy and precision of the method, achieving recovery rates between 86% and 103%, with an RSD of 4.19%. The experimental setup included the AA-1800 spectrometer, lead hollow cathode lamp, and appropriate reagents such as 10% nitric acid and blood lead standard solutions. A standard curve was prepared using different concentrations of lead, ranging from 5.43 µg/L to 55.1 µg/L, with a linear correlation coefficient (R²) of 0.9992. Sample preparation involved taking 50 µL of anticoagulated blood, adding 300 µL of 10% HNO3, mixing, and centrifuging before analyzing the supernatant. The results were calculated using the standard curve and adjusted for dilution factors. The temperature program for the graphite furnace was optimized to reduce splashing, with steps including drying, ashing, atomization, and cleaning. Precision tests showed low variability, with an average RSD of 4.19%. Recovery experiments confirmed the method's reliability. Additionally, the stability of the treated samples was evaluated, revealing that blood samples remain stable for up to 2 hours after treatment. Beyond that, the results become unreliable, emphasizing the need for prompt analysis. Overall, this method offers a fast, accurate, and sensitive approach for measuring lead levels in whole blood. It requires only a small amount of sample, making it suitable for pediatric testing. The technique is ideal for large-scale screening of lead levels in children, contributing to public health monitoring and prevention.