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 mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...
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, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past grouping ...
, which contain one or more aromatic rings, are slightly more polarizable. The remaining two fractions, resins and
asphaltenes
Asphaltenes are molecular substances that are found in crude oil, along with resins, aromatic hydrocarbons, and saturates (i.e. saturated hydrocarbons such as alkanes). The word "asphaltene" was coined by Boussingault in 1837 when he noticed tha ...
, 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 used to separate non-volatile mixtures.
Thin-layer chromatography is performed on a sheet of an inert substrate such as glass, plastic, or aluminium foil, which is coated with a t ...
(TLC) with
flame ionization detection
A flame ionization detector (FID) is a scientific instrument that measures analytes in a gas stream. It is frequently used as a detector in gas chromatography. The measurement of ion per unit time make this a mass sensitive instrument. Standalo ...
(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.
See also
*
Crude oil assay A crude oil assay is the chemical evaluation of crude oil feedstocks by petroleum testing laboratories. Each crude oil type has unique molecular and chemical characteristics. No two crude oil types are identical and there are crucial differences in ...
*
PONA number The PONA number is an index for oil components. It is used to determine the paraffins (P), olefins (O), naphthenes (N) and aromatics (A) content of FCC ( fluid catalytic cracking) and coker ( visbreaker) gasoline.
The PONA number is significant i ...
*
PIONA
Colico ( Comasque: or ; la, Colicum) is a city in the province of Lecco, Lombardy, Italy. It is situated on the northern arm of Lake Como, where the river Adda enters the lake. Colico is the most important city in the northern part of Lake Co ...
*
PNA analysis
PNA or Pna has a variety of meanings:
Science and engineering
* abbreviation for orchid genus ''Paphinia''
* Pacific–North American teleconnection pattern, a climatic phenomenon
* Parisiensia Nomina Anatomica, the revision of anatomic nomencla ...
References
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Petroleum technology