Unsaturated Hydrocarbon Testing

Comprehensive Unsaturated Hydrocarbon Testing – Advanced Qualitative and Quantitative Characterisation for Petrochemical, Environmental, and Materials Applications

Unsaturated hydrocarbons – including alkenes, alkynes, and aromatic compounds – are fundamental building blocks in the chemical industry, serving as monomers for polymers, intermediates for fine chemicals, and key components in fuels. However, their reactivity and instability make accurate detection and quantification challenging, especially in complex matrices such as crude oil, process streams, environmental samples, or polymer degradation products. Customers seeking unsaturated hydrocarbon testing typically need to verify product purity, monitor reaction progress, assess environmental contamination, or troubleshoot quality issues. Routine GC‑FID analysis often fails to resolve positional isomers, distinguish between conjugated and non‑conjugated dienes, or detect trace oxygenated derivatives that indicate oxidation. Our unsaturated hydrocarbon testing service delivers a comprehensive, multi‑technique approach that combines high‑resolution separation, definitive structural identification, and precise quantification – down to parts‑per‑billion (ppb) levels – using state‑of‑the‑art instrumentation and validated methods. We provide the analytical depth needed to solve complex characterisation problems across the entire hydrocarbon value chain.

Who Needs Unsaturated Hydrocarbon Analysis and What Are the Critical Challenges?

Our clients include petrochemical refiners monitoring olefin feedstocks for polymerisation, specialty chemical manufacturers optimising catalytic hydrogenation or oxidation processes, environmental testing laboratories assessing soil and water contamination by fuel components, pharmaceutical companies characterising unsaturated intermediates, and academic researchers investigating novel synthetic pathways. Common difficulties include: co‑elution of olefinic isomers in gas chromatography, instability of alkynes during sample preparation, oxidation artefacts from air exposure, and lack of reference standards for novel branched or cyclic unsaturated species. Our service addresses these by employing hyphenated techniques (GC‑MS, LC‑MS, GC‑xGC, comprehensive two‑dimensional chromatography) and reaction‑based derivatisation (e.g., bromine number, epoxidation, or Diels‑Alder trapping) to stabilise labile analytes and enhance detection sensitivity.

Our Comprehensive Analytical Framework for Unsaturated Hydrocarbon Detection

We employ a modular, problem‑driven approach that selects and combines the most appropriate techniques for your specific sample matrix, target analytes, and required detection limits. Our capabilities span volatile to semi‑volatile and heavy unsaturated compounds, covering C₂ to C₄₀+ hydrocarbons.

1. High‑Resolution Gas Chromatography with Advanced Detection

For volatile and semi‑volatile unsaturated hydrocarbons, we use capillary GC with multiple detectors: flame ionisation (FID) for universal quantification, sulfur‑ or nitrogen‑chemiluminescence for selective detection, and mass spectrometry (MS) for structural confirmation. We employ comprehensive two‑dimensional GC (GC×GC) with modulation to separate co‑eluting isomers – particularly critical for distinguishing cis/trans alkenes, positional olefins, and branched vs. linear alkynes. Our GC×GC‑TOF‑MS system provides high‑resolution mass spectra and structured chromatograms that enable reliable identification even without reference standards, using library matching and retention index prediction.

2. Liquid Chromatography for High‑Molecular‑Weight and Polar Unsaturates

For heavier unsaturated compounds (e.g., polycyclic aromatic hydrocarbons, oligomers, or functionalised alkenes), we employ ultra‑high‑performance liquid chromatography (UHPLC) coupled with photodiode array (PDA) and high‑resolution mass spectrometry (HRMS). We use silver‑ion (Ag⁺) chromatography to separate olefins by degree of unsaturation and geometry, and reversed‑phase systems with specialised stationary phases (e.g., C30 or porous graphitic carbon) for shape‑selective separations. This approach is particularly effective for analysing unsaturated lipids, terpenes, and polymer additives.

3. Spectroscopic Structure Elucidation (NMR, IR, UV‑Vis)

For unknown or novel unsaturated compounds, we provide definitive structure determination using multinuclear and multidimensional NMR (1H, 13C, DEPT, COSY, HSQC, HMBC). We identify olefinic proton environments, coupling constants (to determine E/Z geometry), and alkyne carbon signals. FT‑IR spectroscopy with ATR or transmission cells complements NMR by confirming functional groups (C=C, C≡C, C‑H out‑of‑plane bends) and detecting oxidation products (carbonyl, hydroxyl). For quantification of conjugated dienes or aromatic systems, we use UV‑Vis spectrophotometry with calibrated methods (e.g., diene value by maleic anhydride adduct formation).

4. Determination of Iodine Number, Bromine Index, and Total Unsaturation

For quality control of bulk materials, we offer classical titrimetric methods – iodine value (Wijs method) and bromine index (ASTM D1159) – which provide total unsaturation content (g I₂/100 g or mg Br/100 g). However, we go further by coupling these with automated potentiometric titration and digital colourimetric end‑point detection to improve precision and reduce operator dependency. We also provide determination of diene value via maleic anhydride adduction and subsequent titration, to distinguish conjugated from non‑conjugated unsaturation.

5. Trace‑Level Analysis and Matrix‑Matched Calibration

Environmental and ultrapure applications require detection at sub‑ppm or ppb levels. We achieve this through solid‑phase microextraction (SPME), purge‑and‑trap, or large‑volume injection (LVI) techniques, combined with tandem mass spectrometry (MS/MS) for selective reaction monitoring. We develop matrix‑matched calibration standards to compensate for matrix effects (e.g., from crude oil, wastewater, or polymer extracts), and we use isotope‑labelled internal standards (e.g., deuterated alkenes) to correct for extraction efficiency and instrument drift. Our LODs for individual unsaturated hydrocarbons typically range from 0.1 to 10 ppb in water and 1 to 50 ppm in solid matrices.

6. Stability and Artefact Monitoring During Sample Handling

Unsaturated compounds are susceptible to autoxidation, polymerisation, and isomerisation during storage and preparation. We implement controlled inert‑atmosphere sampling (glovebox or nitrogen‑blanketed vessels), addition of antioxidants (BHT, BHA), and low‑temperature handling to preserve sample integrity. We also perform stability studies on your specific sample matrix to determine the acceptable holding time and storage conditions, and we include recovery tests for spiked analytes to verify that our protocol minimises losses.

7. Speciation of Unsaturated Hydrocarbons in Complex Matrices (Petroleomics)

For heavy petroleum fractions or bio‑oils, we apply Fourier‑transform ion cyclotron resonance mass spectrometry (FT‑ICR MS) with electrospray or atmospheric‑pressure chemical ionisation to resolve thousands of unsaturated compound classes (e.g., aromatics with varying degrees of unsaturation, S‑containing thiophenes, N‑containing pyrroles). We generate double‑bond equivalent (DBE) vs. carbon number plots to visualise the distribution of unsaturation, enabling detailed fingerprinting for feed compatibility, process optimisation, or environmental source apportionment.

8. Accelerated Oxidation Stability Testing

For materials prone to oxidative degradation (e.g., unsaturated oils, fuels, or monomers), we perform Rancimat (EN 14112) and PetroOxy tests to measure oxidation induction time (OIT) at elevated temperature and oxygen pressure. We complement these with real‑time FTIR monitoring of hydroperoxide formation and GC‑MS tracking of volatile oxidation products (aldehydes, ketones). This provides a comprehensive picture of oxidative stability and helps predict shelf life or formulate effective antioxidants.

Our Distinctive Advantages in Unsaturated Hydrocarbon Testing

Our laboratory is uniquely equipped with an integrated suite of separation and spectroscopy platforms that allows us to tackle any unsaturation‑related problem, from routine quality control to cutting‑edge research. We maintain a dedicated unsaturated‑hydrocarbon handling facility with oxygen‑free gloveboxes and cryogenic sample preparation, ensuring artefact‑free results for air‑sensitive samples. Our instrument fleet includes: a two‑dimensional GC×GC‑TOF‑MS, a UHPLC‑HRMS (Orbitrap), a 600 MHz NMR with cryoprobe, and a FT‑ICR MS (available via our collaboration network).

Our team consists of analytical chemists, petroleomic specialists, and synthetic organic chemists who understand the chemistry of unsaturation – including isomerisation mechanisms, Diels‑Alder reactivity, and metal‑catalysed hydrogenation. We do not merely report concentrations; we interpret the results in the context of your process – for example, linking a change in cis/trans ratio to catalyst ageing, or correlating polyene content with gum formation in fuels. We also provide method development and validation services according to ICH, USP, or EPA guidelines, and we can transfer validated methods to your in‑house laboratory.

All testing follows strict quality protocols under ISO/IEC 17025, with participation in proficiency testing schemes (e.g., ASTM interlaboratory studies). Our reports include measurement uncertainty and confidence intervals, ensuring that your decisions are based on statistically sound data.

Deliverables – A Tailored Analytical Report for Your Needs

Your final report will be customised to your application, but typically includes:

Section 1 – Executive summary: Key findings, compliance with specifications, and any anomalies requiring attention.

Section 2 – Quantitative results: Concentration of each identified unsaturated hydrocarbon, with individual or summed values (e.g., total alkenes, total alkynes, total aromatics), and comparison with regulatory or customer limits.

Section 3 – Qualitative identification: Structural assignments (cis/trans, branching, conjugation) supported by MS, NMR, or IR spectra, with confidence levels.

Section 4 – Chromatographic and spectral data: Representative chromatograms (GC‑FID, GC×GC, UHPLC), mass spectra, and NMR/FTIR plots, annotated for clarity.

Section 5 – Stability and artefact assessment: Recovery rates, storage stability data, and any precautions for future sampling.

Section 6 – Methodological details: Fully described procedures, calibration ranges, LOD/LOQ, and validation statistics.

Section 7 – Expert interpretation and recommendations: Our chemists’ insights into the significance of the data, potential sources of variability, and suggestions for process improvements or further investigations.

All raw data files (chromatograms, spectra, titration curves) are provided in standard digital formats (AIA, JCAMP, CSV).

Industries and Applications We Support

Our unsaturated hydrocarbon testing serves petrochemical and refinery operations (feedstock characterisation, product certification), polymer and elastomer producers (monomer purity, oligomer analysis), fuel and lubricant manufacturers (stability, composition), environmental consulting firms (site remediation, spill fingerprinting), pharmaceutical and flavour/fragrance industries (intermediate purity), and academic research (mechanistic studies, new compound discovery).

How to Start Your Unsaturated Hydrocarbon Testing Project

Engaging our service is straightforward and collaborative:

1. Consultation: We discuss your sample matrix, target unsaturates, required detection limits, and any known handling difficulties (air sensitivity, volatility, matrix interferences).

2. Custom proposal: We design a test plan with the most appropriate techniques and provide a fixed price and timeline – typically 5–10 working days for routine analysis, with faster options for urgent requests.

3. Sample submission: We supply detailed sampling and shipping instructions (inert atmosphere, amber glass, cold chain) to ensure sample integrity.

4. Analysis and interim review: We perform the tests and share preliminary results for your feedback, allowing adjustments if unexpected peaks or interferences are encountered.

5. Final report and interpretive session: You receive the comprehensive report and we schedule a virtual meeting to discuss the findings, answer technical questions, and recommend further actions.

We maintain strict confidentiality under a standard NDA, and we can accommodate both single‑sample projects and long‑term monitoring programmes with volume discounts.

Conclusion – Trust Our Expertise for Reliable Unsaturated Hydrocarbon Characterisation

Accurate detection and quantification of unsaturated hydrocarbons require a combination of advanced separation, sensitive detection, and deep chemical understanding – all of which are at the core of our service. Our unsaturated hydrocarbon testing provides the analytical rigor and interpretative insight you need to ensure product quality, meet regulatory obligations, and advance your research. With a comprehensive instrument portfolio, expert staff, and a commitment to data integrity, we are your ideal partner for tackling the most demanding unsaturated hydrocarbon analysis challenges.

Contact our analytical specialists today to discuss your project and receive a tailored proposal. Let us help you gain the clarity you need from your unsaturated hydrocarbon samples.