For the quantitative in vitro determination of magnesium in serum. A colorimetric xylidyl blue complex method.
Principle
Magnesium ion forms a colored complex with xylidyl blue under alkaline conditions. The intensity of the developed color is proportional to the magnesium ion concentration of the sample.
Precautions:
1. This reagent is for in vitro diagnostic use only.
2. Do not pipette by mouth. Avoid contact with skin and clothing.
REAGENT PREPARATION
The reagent is ready for use.
REAGENT DETERIORATION
Do not use reagent if:
1. Reagent fails to achieve established values of fresh control sera.
2. Reagent becomes visibly turbid.
3. Reagent has an absorbance greater than 1.2 when measured against water at 500(480-520) nm.
SPECIMEN COLLECTION AND STORAGE
1. Use fresh, unhemolyzed serum.
2. Red cells contain twice the magnesium concentration as serum. A hemolyzed sample would falsely elevate results.
3. Grossly icteric or lipemic specimens should not be used in this method.
4. Urine (diluted in ratio of 1:10 with distilled water). The sample should be adjusted to pH 3 - 4 with diluted hydrochloric acid
ADDITIONAL EQUIPMENT REQUIRED BUT NOT PROVIDED
1. A clinical chemistry analyzer capable maintaining constant temperature (37°C), and measuring absorbance at 500 nm (480-520).
2. Deionized water and related equipment, e.g.: pipettes
3. Analyzer specific consumables, e.g.: sample cups
4. Control and calibrator materials.
PROCEDURE
System Parameters
Temperature : 37°C
Wavelength : 500 nm(480 – 520)
Optical Path : 1 cm
Assay Type : Endpoint