1 Yellow media without gas pocket-sugar utilization with production of acid only. 2  Red media (no change in media) -no change and no sugar utilization. 3  Pink media especially at the top, ignore gas-no sugar utilization with degradation of protein resulting in alkaline end products (this may be difficult to see).
With organic solvents with long alkane chain, such as n-hexadecane and n-decane, the water droplets become much larger and the microemulsion is unstable. In this case, solvent polarity may have become a determining factor and the long alkane chain was too hydrophobic to form a stable microemulsion with water.
Commercial hexane contains a mixture of hexane isomers (n-hexane, 2-methyl pentane, 3-methyl pentane, 2,3-dimethylbutane), cyclohexane, methyl cyclopentane,pentane and heptane isomers The n-hexane content varies from 20 to 80%. (IPCS 1991)