Lugol's source/paying less and making sure it's the right stuff

I thought $9.95/oz. at jcrows was high, so I went with sciencecompany.com, which carries reagent-grade Lugol's at $13.75 for 4 oz. It is 5% Iodine and 10% potassium iodide. Their shipping costs were about $7 for UPS ground, and shipping was quick.

Some products sold as Lugol's solution do have lower concentrations of iodine. I have found staining solutions sold for microscopy which are 1% Iodine and 2% iodide, and another Lugol's formulation called Weigert stain which is 4.15% Iodine and 6.3% potassium iodide.

If you're not sure exactly what's in the Lugol's being sold by a chemical supply house, the information about the concentration in the solution is usually found in the Materials Safety Data Sheet (MSDS).