Megazyme produces 2 different glycerol test kits: 

Both test kits provide equal performance and specificity for the measurement of glycerol.

K-GCROLGKuses the more recently developed and more robust glucokinase reaction which allows for the detection and measurement of glycerol with an increase in absorbance.  Manual and automated format for use with both spectrophotometers and auto-analysers.

K-GCROL: uses the traditional pyruvate detection method which provides a negative absorbance reaction.  Manual format for use with spectrophotometers.

Product Page (K-GCROL)

Product Page (K-GCROLGK)