The Chromatographic Party in Valencia
When Separation Science Took Center Stage at ISC 2010
The Science of Separation
Imagine trying to identify every ingredient in a complex recipe just by tasting the final dish—an nearly impossible task. This is the challenge scientists face when analyzing complex mixtures, from environmental samples to pharmaceutical compounds.
Chromatography, the revolutionary scientific method that separates mixtures into their individual components, makes this possible. In September 2010, the global community of separation scientists gathered in Valencia, Spain, for the 28th International Symposium on Chromatography (ISC 2010)—an event that showcased both the established principles and cutting-edge advancements in this crucial scientific field.
Though the name might suggest colorful displays, chromatography actually derives from Greek words meaning "color writing," a nod to its early use in separating plant pigments. Today, it represents one of the most powerful analytical techniques available to scientists across disciplines. The Valencia symposium served as both a celebration of past achievements and a launching pad for future innovations in this essential scientific discipline 1 4 .
A Conference of Separation: ISC 2010 in Focus
From September 12-16, 2010, Valencia hosted an intellectual feast that brought together 570 registered participants from around the world. The conference, organized by the Spanish Association of Chromatography and Related Techniques (SECyTA), marked a return to Spain after 36 years—the tenth symposium had been held in Barcelona in 1974 1 .
570
Registered Participants
122
Oral Presentations
22
Exhibiting Companies
4
Major Awards
Award Winners at ISC 2010
| Award | Recipient(s) | Institution |
|---|---|---|
| Tswet & Nernst Prize | Guenther Bonn | University of Innsbruck, Austria |
| Tswet & Nernst Prize | Vadim A. Davankov | Russian Academy of Sciences, Russia |
| EuSSS Under-35 Award | María Ibáñez Martínez | University Jaume I, Spain |
| José Antonio García Domínguez Award (Oral) | M. Nocun and J.T. Andersson | University of Münster, Germany |
The Fundamentals: More Than Just Color Writing
To appreciate the developments presented in Valencia, one must first understand chromatography's basic principles. At its simplest, chromatography separates mixtures by distributing components between two phases: one stationary and one mobile 4 .
The process begins when a mixture is dissolved in a fluid (the mobile phase), which carries it through a system containing a stationary phase. As different components have varying affinities for the stationary phase, they travel at different velocities—creating separation based on how strongly each component interacts with the stationary material 4 .
Think of it as a race where competitors are repeatedly stopped for photographs. Those less interested in being photographed (with lower affinity for the stationary phase) move quickly ahead, while those who pose repeatedly (with higher affinity) fall behind. This differential migration results in the separation of components .
Two Phases
Stationary and mobile phases work together to separate components based on their chemical properties.
The Chromatographic Family Tree
Several chromatographic techniques have evolved from Mikhail Tsvet's original 1901 method 4 :
Uses gaseous mobile phases and requires volatile, thermally stable analytes. Ideal for petroleum hydrocarbons, pesticides, and environmental contaminants .
Employs liquid mobile phases for non-volatile or thermally labile compounds. Widely used for pharmaceuticals, organic acids, and proteins 3 .
Features a stationary phase coated on a flat plate. Excellent for quick, simple separations and educational demonstrations 4 .
Leverages specific biological interactions for purification. Essential for enzyme purification and antibody isolation 3 .
Common Chromatography Types and Their Applications
| Technique | Mobile Phase | Best For | Common Applications |
|---|---|---|---|
| Gas Chromatography (GC) | Gas (e.g., Helium) | Volatile, thermally stable compounds | Petroleum hydrocarbons, pesticides, environmental contaminants |
| Liquid Chromatography (LC/HPLC) | Liquid solvents | Non-volatile or thermally labile compounds | Pharmaceuticals, organic acids, vitamins, proteins 3 |
| Thin-Layer Chromatography (TLC) | Liquid (capillary action) | Quick, simple separations | Screening applications, educational demonstrations 4 |
| Affinity Chromatography | Liquid | Biological molecules with specific interactions | Enzyme purification, antibody isolation 3 |
The Pursuit of Perfect Separation: Resolution and Peak Capacity
A central theme at ISC 2010 was the ongoing quest for better separation efficiency—a concept chromatographers quantify as "resolution" 2 .
Chromatographic Resolution (Rs)
Measures how well two adjacent peaks are separated in a chromatogram. It depends on both the distance between peak maxima and their widths.
Mathematically, it's expressed as Rs = Δt/(4σ), where Δt is the difference in retention times and σ is the standard deviation of a Gaussian peak 2 .
Resolution Values
- Rs = 1.0: Peaks are partially separated with about 2% overlap—often sufficient for qualitative but not quantitative analysis
- Rs = 1.5: Considered "baseline separation" with only 0.1% overlap—the gold standard for accurate quantification 2
As one expert explains: "To achieve near baseline separation of two adjacent peaks, the distance between the two peak maxima must be equal to 6σ. At this value, each peak would overlap its neighbor by only 0.1%" 2 .
Another important concept discussed was "peak capacity"—the maximum number of peaks that can be crowded into a separation space with resolution equal to one. For typical HPLC columns using isocratic elution, peak capacity is less than 100, but much higher for gradient elution 2 .
Visualizing Resolution
[Interactive chart showing chromatographic peaks with different resolution values would appear here]
Beyond the Laboratory: Real-World Applications
The Valencia symposium highlighted chromatography's expansive role in solving real-world problems. The special issue of Analytical and Bioanalytical Chemistry stemming from the conference revealed the technique's diverse applications 1 :
Food and Environmental Safety
Chromatography serves as our first line of defense in detecting contaminants in food and the environment. Presentations at ISC 2010 featured methods for identifying pesticides in soil and water, veterinary drug residues in milk and eggs, and ochratoxin A in wine 1 . These applications are crucial for ensuring food safety and monitoring environmental health.
Industrial and Pharmaceutical Applications
From analyzing carotenoids in juices to characterizing pharmaceutical compounds, chromatographic methods presented at the conference addressed quality control across industries. The analysis of perfluorinated compounds highlighted chromatography's role in tracking industrial pollutants 1 .
Biological and Medical Research
Affinity chromatography, in particular, has revolutionized biological research. As one resource notes: "Today, affinity chromatography has been widely used in the separation and purification of biomolecules. It is one of the most important methods for separating and purifying biological macromolecules..." 3 .
Chromatography Application Timeline
Early 20th Century
Mikhail Tsvet develops the first chromatographic technique to separate plant pigments, coining the term "chromatography" 4 .
1940s-1950s
Paper chromatography and gas chromatography are developed, expanding applications to amino acids and volatile compounds.
1960s-1970s
High-performance liquid chromatography (HPLC) emerges, dramatically improving separation efficiency and speed.
1980s-1990s
Coupling chromatography with mass spectrometry becomes routine, enabling precise compound identification.
2000s-Present
Multidimensional techniques (GC×GC, LC×LC) and miniaturized systems push the boundaries of separation power .
Inside the Laboratory: A Featured Experiment
To understand how chromatographers work, let's examine a hypothetical but representative experiment similar to those presented at ISC 2010—the analysis of carotenoid pigments in orange juice from different geographical origins.
Methodology
- Sample Preparation: Orange juice samples are first extracted using solvent mixtures. Solid-phase extraction cartridges clean up the extracts to remove sugars and other interfering compounds.
- Instrumental Analysis: The purified extracts are injected into a High-Performance Liquid Chromatography system equipped with a reversed-phase C18 column and a photodiode array detector.
- Separation Conditions: The mobile phase consists of acetonitrile and methanol with gradient elution—starting with 90% organic phase and increasing to 100% over 20 minutes.
- Detection: Carotenoids are detected at 450 nm, their characteristic absorption wavelength.
- Data Analysis: Software processes the chromatograms, identifying peaks based on retention times and spectral characteristics compared with authentic standards.
A modern HPLC system used for carotenoid analysis in food samples.
Results and Significance
This experiment would typically yield distinct chromatographic profiles for different orange varieties and growing regions. For example, Valencia oranges might show higher concentrations of specific carotenoids like lutein or β-cryptoxanthin compared to Navel oranges.
The scientific importance lies in the ability to:
- Authenticate food origins and detect adulteration
- Correlate pigment profiles with nutritional value
- Understand how growing conditions affect fruit composition
Such experiments exemplify chromatography's power in both fundamental research and practical applications like food authentication.
Hypothetical Carotenoid Composition of Orange Juices (Relative Peak Areas)
| Carotenoid | Valencia Oranges (Spain) | Navel Oranges (USA) | Tangerines |
|---|---|---|---|
| Lutein | 15.2 | 12.8 | 8.5 |
| Zeaxanthin | 8.7 | 6.9 | 10.2 |
| β-Cryptoxanthin | 22.1 | 18.5 | 35.8 |
| α-Carotene | 5.3 | 4.7 | 12.4 |
| β-Carotene | 18.6 | 15.3 | 22.7 |
The Scientist's Toolkit: Essential Research Reagents and Materials
Chromatographers rely on specialized materials to achieve their separations. Here are key components from the scientist's toolkit:
Stationary Phases
- Silica-based C18: The workhorse of reversed-phase chromatography; provides hydrophobic interactions for separating non-polar compounds
- Ion-exchange resins: Feature charged groups for separating ionic species
- Affinity matrices: Contain immobilized biological ligands for specific binding
- Size exclusion gels: Porous materials that separate by molecular size
Mobile Phase Components
- High-purity solvents: Water, acetonitrile, methanol—often HPLC-grade to prevent contaminants
- Buffer systems: Control pH and mask undesirable interactions; ammonium acetate and phosphate buffers are common
- Ion-pairing reagents: Improve separation of ionic compounds
Columns and Hardware
- Analytical columns: Typically 100-250mm long, 1-5mm in diameter, packed with micron-sized particles
- Guard columns: Protect main columns from contamination
- In-line filters: Remove particulate matter that could damage columns
Detection Systems
- UV-Vis detectors: Measure light absorption at specific wavelengths
- Mass spectrometers: Provide molecular identity and structural information
- Fluorescence detectors: Offer high sensitivity for fluorescent compounds
Conclusion: The Enduring Legacy of Separation Science
The 2010 Chromatography Symposium in Valencia represented both a celebration of past achievements and a looking forward to chromatography's future.
As the field continues to evolve, with developments in multidimensional techniques like GC×GC and LC×LC that provide dramatically improved separations, the core principles demonstrated in Valencia remain relevant .
Chromatography has come a long way from Mikhail Tsvet's simple color separations, but the fundamental goal remains unchanged: to separate complex mixtures into their individual components for identification and quantification. The "chromatographic party" in Valencia highlighted both the established utility and exciting future of this essential scientific technique—one that continues to shape fields as diverse as environmental science, food safety, pharmaceutical development, and biological research.
As one of the conference organizers noted, "the area of separation science is an exciting and rapidly moving field, and we look forward to many new analytical advances in the coming years" 1 . With each passing symposium, chromatographers continue to push the boundaries of what's possible in separation science, ensuring that this century-old technique remains at the forefront of analytical science.