science

Petroleomics

Petroleomics is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Petroleomics rather than just read about it. In short: Petroleomics is the identification of the totality of the constituents of naturally occurring petroleum and crude oil using high resolution mass spectrometry. In addition to mass determination, petroleomic analysis sorts the chemical compounds into heteroatom class (nitrogen, oxygen and sulfur), type (degree of unsaturation), and carbon number.

Key takeaways

Petroleomics belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Petroleomics to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Petroleomics from memory before moving on to harder problems.

Reference excerpt

Petroleomics is the identification of the totality of the constituents of naturally occurring petroleum and crude oil using high resolution mass spectrometry. In addition to mass determination, petroleomic analysis sorts the chemical compounds into heteroatom class (nitrogen, oxygen and sulfur), type (degree of unsaturation), and carbon number. The name is a combination of petroleum and -omics (collective chemical characterization and quantification).

History

Mass spectrometry characterization of petroleum has been performed since the first commercial mass spectrometers were introduced in the 1940s. Early mass spectrometry was limited to relatively low molecular weight nonpolar species accessed mainly by electron ionization with mass analysis with sector mass spectrometers. By the end of the 20th century, separations combined with mass spectrometric techniques such as gas chromatography-mass spectrometry and liquid chromatography mass spectrometry have characterizated petroleum distillates such as gasoline, diesel, and gas oil. The first petroleum analysis with electrospray ionization was demonstrated in 2000 by Zhan and Fenn, who studied the polar species in petroleum distillates with low-resolution MS. Electrospray ionization was coupled with high-resolution FT-ICR by Marshall and coworkers. To date, many studies on petroleomic analysis of crude oils have been published. Most work has been done by the group of Marshall at the National High Magnetic Field Laboratory (NHMFL) and Florida State University.

Ionization methods

Ionization of nonpolar petroleum components can be achieved by field desorption ionization and atmospheric pressure photoionization (APPI). field desorption FT-ICR MS has enabled the identification of a large number of nonpolar components in crude oils that are not accessible by electrospray, such as benzo- and dibenzothiophenes, furans, cycloalkanes, and polycyclic aromatic hydrocarbons (PAHs). A drawback of field desorption is that it is slow, mainly due to the need of ramping the current to the emitter in order to volatilize and ionize molecules. APPI can ionize both polar and nonpolar species, and an APPI spectrum can be generated in just a few seconds. However, APPI ionizes a broad range of compound classes and produces both protonated and molecular ion peaks, resulting in a complex mass spectrum.

Kendrick analysis

High mass resolution data analysis is usually undertaken by converting the mass spectra to the Kendrick mass scale, in which the mass of a methylene unit is set to exactly 14 (CH2 = 14.0000 instead of 14.01565 daltons). This rescaling of the data aids in the identification of homologous series according to alkylation, class (number of heteroatoms), and type (double bond equivalent, DBE, also called rings plus double bonds or degree of unsaturation). The scaled data is then used to obtain the Kendrick mass defect (KMD), which is given by

Kendrick~mass~defect = nominal~Kendrick~mass − Kendrick~mass {\displaystyle {\textrm {Kendrick~mass~defect}}={\textrm {nominal~Kendrick~mass}}-{\textrm {Kendrick~mass}}}

where the nominal Kendrick is the Kendrick mass rounded to the nearest integer. Double bond equivalent (DBE) is calculated according to

R i n g s + π B o n d s = C − H 2 − X 2 + N 2 + 1 {\displaystyle Rings+\pi Bonds=C-{\frac {H}{2}}-{\frac {X}{2}}+{\frac {N}{2}}+1\,}

where C = number of carbons, H = number of hydrogens, X= number of halogens and N = number of nitrogens. O Compounds with the same DBE have the same mass defect. Therefore, Kendrick normalization yields a set of series with identical mass defect that appear as horizontal rows in a plot of DBE versus Kendrick mass. The data can also be plotted as a 3D heat-map to indicate the relative intensity of the mass spectral peaks. From the Kendrick plot, the species with peaks in the mass spectrum can be sorted into compound classes by the number of nitrogen, oxygen and sulfur heteroatoms. The data can also be represented with a Van Krevelen diagram.

Illustrations

Worked examples

Example 1 — a first encounter with Petroleomics

Start with the simplest possible case. Write down what Petroleomics claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Petroleomics before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Petroleomics ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Petroleomics

In research: Petroleomics appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Petroleomics in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Petroleomics is common in secondary-school and first-year university syllabi. It links to neighbouring topics Mass spectrometry, Petroleum, so understanding it makes those chapters shorter.
In everyday life: Look for Petroleomics outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Petroleomics in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Petroleomics means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Petroleomics out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Petroleomics in simple terms?

Why does Petroleomics matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Petroleomics?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Petroleomics.