In gas chromatography, the detector is maintained several degrees cooler than the column temperature. A refractive index detector is susceptible to temperature effects from the atmosphere. Column temperature has only a minor effect on GLC separation. Water activity is a good measure of the moisture content in foods. Dry ashing is a good method for the more volatile elements.
Gravimetric methods are an accurate means of determining the mineral contents of food samples.
In gel filtration chromatography, the small compounds elute first. A 1 liter solution contains 2 moles of lactic acid and 1 mole of lactate ion. The pK of lactic acid is 3.86. What is the pH of this solution. How much lactic acid would you have to add to make the pH to 3.4.