Saturate, Aromatic, Resin and Asphaltene (SARA) is an analysis method that divides

crude oil Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring u ...

components according to their polarizability and polarity. The saturate fraction consists of nonpolar material including linear, branched, and cyclic saturated hydrocarbons ( paraffins).

Aromatics Aromatic compounds or arenes are organic compounds "with a chemistry typified by benzene" and "cyclically conjugated." The word "aromatic" originates from the past grouping of molecules based on odor, before their general chemical properties were ...

, which contain one or more aromatic rings, are slightly more polarizable. The remaining two fractions, resins and asphaltenes, have polar substituents. The distinction between the two is that asphaltenes are insoluble in an excess of heptane (or pentane) whereas resins are miscible with heptane (or pentane).

Method description

There are three main methods to obtain SARA results. One has lately emerged as the most popular. That technology is known as the Iatroscan TLC-FID, and it combines

thin-layer chromatography Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures. It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. This is called the sta ...

(TLC) with flame ionization detection (FID). It is referred to as IP-143. Other analysis giving SARA numbers might not correspond to the numbers obtained in IP-143. It is therefore always important to know the analysis method when comparing SARA numbers. TLC-FID is the only method that is 100 times more sensitive than any of the older methods and faster, taking 30 seconds for 1 sample instead of 1 day. In comparison, IP-143 method can take up to 3 days, and it does not offer any analytical precision.

References

{{reflist Petroleum technology

Method description

See also

References