Sorry for the confusion, I should have explained G.C.
Gas Chromatography is a technique for analyzing organic liquids to determine the ingredients. I’ll start with a plain-word analogy.
Imagine a mixture of different size balls, and you would like to know how many balls there are of each different size. You need to first separate the balls according to size, and then count the number of each size. One way to separate the balls is to roll them through a long tube, which is coated inside with a sticky coating. Each ball sinks into the sticky coating to a different depth depending on its size and shape, so each ball moves along at a different speed. As they move through the tube, the mixture of balls are separated because they move at different speeds, and by the time they make it to the end of the long tube they are separated into groups of balls. The smaller faster moving balls are all grouped together and reach the end of the long tube first. They are followed by a group of the next larger balls, and so on. In short, what the long tube did is slow down the balls according to their size and separate them into size groups, each of which then exits the tube as a group of equal sized balls.
This same principle can be applied to molecules. A motor oil is a mixture of different size and shape molecules, and to see and measure each type you first need to separate them. That’s what a G.C. does. Using a syringe, you inject about 1/1000th of a drop of the oil (a mixture of liquids) into the machine where it hits a very hot tube and boils into a mixture of gases. These gases are swept by an inert gas (helium) into a long thin tube that is coated with special chemicals. As the mixture of gases moves through the long tube, each gas dissolves into the coating and is then pulled out of solution by the helium, that is, they kind of roll through the tube like balls with the speed determined by their solubility in the coating. This separates the gases into groups, each group being a different set of molecules. As each group of molecules exit the tube they are measured and a “peak” is drawn on a graph.
By examining the graph, one can see a series of peaks, each representing a different molecule, and the size of the peak indicates how much is present. The mineral oil graph shows hundreds of peaks, all piled into a pyramid shape because they are a distillation cut containing similar size molecules. PAO looks totally different, showing discreet groups of peaks separated by a flat baseline between them. Esters can have many different looking graphs because there are many different esters. The point is, each base oil has its own unique set of peaks, and the graph serves as a thumbprint that identifies the product and its amount.
What’s it all mean? One could argue that the composition of a motor oil is not very important at all so long as it performs the way you want it to in your car. But on this forum it rises to a supreme level, an “elixir of life”!
I’m just reporting what I find, and I didn’t find esters in the Gold GC. This doesn’t mean it’s not G*d’s gift to car enthusiasts, only that it may achieve this status without esters.
Tom
