Magnesium is a chemical element that forms several different compounds such as magnesium chloride, magnesium citrate, magnesium hydroxide (milk of magnesia), and magnesium sulfate heptahydrate (Epsom salts). Magnesium, through its interaction with phosphate, is essential to the basic nucleic acid chemistry of all cells of all known living organisms. Over 300 enzymes need magnesium ions to catalyze reactions, including all enzymes using or synthesizing ATP as well as those that use other nucleotides to synthesize DNA and RNA. The ATP molecule is typically found in a binding interaction with a magnesium ion.

Magnesium Assay Kit provides a simple, reproducible, and sensitive tool of measuring Magnesium concentration in plasma, serum, cell lysates, saliva, urine, and other biological liquid samples. In this assay, magnesium forms a purple chelate with Xylidyl Blue-I at an alkaline pH. The intensity of this colored complex is proportional to the magnesium concentration in the sample and is measured at 520 nm.

• Microplate reader capable of measuring absorbance at 520 nm
• Precision pipettes to deliver 2 µL to 1 mL volumes
• Tubes to prepare sample dilutions
• 5 mL tubes
• MilliQ water or another type of double distilled water (ddH₂O)

1. Add 10 µL of the diluted Magnesium Standards or samples to the 96-well microtiter plate.
2. Initiate the reaction by adding 200 µL Working Solution to all wells. Carefully shake the plate for a few seconds to mix.
3. Incubate the plate for 10 minutes at room temperature with mixing in the dark.
4. Measure the absorbance at 520 nm using a plate reader.