This application note describes a method for the determination of calcium and magnesium in blood serum and urine using atomic absorption spectrophotometry.
This document outlines the application of atomic absorption spectrophotometry for analyzing calcium and magnesium in clinical materials, specifically blood serum and urine. It details sample preparation methods, including dilution factors and the use of reagents like lanthanum chloride or strontium chloride to suppress interferences from proteins and phosphates.
The note provides specific instrumental settings for the Techtron Model 1000 atomic absorption spectrophotometer, including resonance lines, lamp currents, and burner types. It also discusses the effects of flame type (air-acetylene vs. nitrous oxide-acetylene) on sensitivity and includes calibration data.
| Resonance Line (Calcium) | 4226.7 A |
|---|---|
| Resonance Line (Magnesium) | 2852.1 A |
| Photomultiplier (Calcium) | R-213 |
| Lamp Current (Calcium) | 4mA |
| Lamp Current (Magnesium) | 3mA |
| Spectral Band Pass | 2 A |
| Flame Type (Calcium) | N2O-C,H Air-C,H |
| Burner (Calcium) | AB-50, 5 cm |
| Burner (Magnesium) | AB-51, 10 cm |
| Sample Volume (Serum) | 0.5 mL |
| Sample Volume (Urine) | 0.5 mL |
The use of the nitrous oxide-acetylene flame is recommended for the determination of calcium at the 4226.7 A resonance line.
Magnesium is determined in the air-acetylene flame at the 2852.1 A resonance line.
The lanthanum present in the solutions will control interference effects and act as an ionization suppressant.
If nitrous oxide is not available, an air-acetylene flame may be employed, but the sensitivity is approximately 3X less.