Enhancing Forensic Fingerprint Analysis: How the MICROVAP Sample Concentrator Aids Solvent Removal

June 24, 2025 /

Dr. Petr Vozka's innovative research at California State University, Los Angeles is advancing the field of forensic chemistry through the comprehensive analysis of fingerprint aging. The Complex Chemical Composition Analysis Lab (C³AL) utilizes cutting-edge comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) to analyze fingerprint chemical composition changes over time [1]. Central to this complex analytical workflow is Organomation's 15 position MICROVAP nitrogen evaporator, which plays a crucial role in sample preparation and concentration. This case study explores how the integration of the MICROVAP system has enhanced sample processing efficiency, improved reproducibility, and ultimately contributed to groundbreaking discoveries in fingerprint aging research that could transform forensic investigations.

Background: Dr. Vozka's Pioneering Fingerprint Research

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Dr. Petr Vozka serves as an Assistant Professor of Analytical Chemistry at California State University, Los Angeles, where he established the Complex Chemical Composition Analysis Lab (C³AL). His research facility has emerged as a beacon of opportunity for first-generation and underrepresented students, providing hands-on experience with advanced analytical instrumentation. The lab's partnership with LECO Corporation has been transformative, equipping students with access to a state-of-the-art comprehensive two-dimensional gas chromatography system [2]. This collaboration was formalized in 2023 when LECO presented Dr. Vozka with a GC×GC-enabled Pegasus TOFMS system in recognition of his extensive work in microplastics analysis using GC×GC technology, as well as his efforts in training the next generation of GC×GC users [2].

Among Dr. Vozka's most promising research initiative is his collaboration with the Hertzberg-Davis Forensic Science Center on fingerprint aging research. This innovative project aims to understand how fingerprint components change over time, with the ultimate goal of developing a reliable aging model that could revolutionize forensic investigations [3]. The significance of this research extends beyond academic interest, potentially providing law enforcement with crucial temporal information about when fingerprints were deposited at crime scenes. By analyzing the complex chemical composition of fingerprints and monitoring how specific compounds degrade or transform over time, Dr. Vozka's team is laying the scientific groundwork for fingerprint chronology, an area that has traditionally depended on circumstantial evidence or witness testimony [3].

The Fingerprint Analysis Workflow Challenge

The analytical workflow for fingerprint aging analysis presents several challenges that require an innovative solution. The process begins with careful sample collection, where technicians moisten cotton swabs with dichloromethane and methodically swab the fingerprint from its surface [3]. This initial extraction captures numerous organic compounds present in fingerprints, with primary targets including cholesterol metabolites and squalene [3]. However, these compounds exist in extremely low concentrations in fingerprints, making their detection and quantification particularly challenging without proper sample preparation and concentration steps.

Before these samples can be analyzed using the GC×GC-TOFMS system, they must undergo a critical concentration step to remove excess solvent while preserving the target analytes [4]. This intermediate step posed several technical hurdles for Dr. Vozka's research team. Manual evaporation methods were time-consuming and introduced significant variability between samples, potentially compromising the reliability of their aging models. Inconsistent evaporation rates and temperatures could lead to selective loss of volatile compounds, skewing the chemical profile of the fingerprint samples. Additionally, the research involved processing multiple samples from different time points to track changes over time, creating a workflow bottleneck with traditional single-sample evaporation methods.

The precision required for forensic applications added another layer of complexity to the sample preparation process. Even minor variations in concentration technique could significantly impact the final analytical results and the validity of any aging models developed. The research team needed a solution that could provide controlled, reproducible evaporation for multiple samples simultaneously, while maintaining the integrity of the complex mixture of compounds present in fingerprint residues [4]. This critical stage in the analytical workflow presented an ideal opportunity for technological intervention to enhance both throughput and data quality.

The MICROVAP: Efficient Sample Concentration

The 15 position MICROVAP nitrogen evaporator from Organomation emerged as the ideal solution for Dr. Vozka's fingerprint analysis workflow. This compact benchtop evaporator is specifically designed for small batch solvent evaporations, such as concentrations of sample groups in microcentrifuge tubes, making it perfectly suited for the fingerprint extract samples collected on dichloromethane-moistened swabs [5]. The system's ability to simultaneously process up to 15 samples significantly improved laboratory throughput, allowing the research team to analyze multiple fingerprint samples within a single batch [4, 5]. This capability is especially valuable in fingerprint aging studies, where comparing samples collected at different time intervals is essential for developing accurate temporal models.

The MICROVAP's precision temperature control, ranging from room temperature to 130°C with accuracy of ± 2°C, provides the careful regulation necessary for compound preservation during the concentration process. This feature is critical when working with fingerprint samples that contain a complex mixture of target compounds which may be susceptible to evaporation or degradation under higher temperature conditions. The newly redesigned heating unit offers enhanced heat stability for low-temperature applications, which is crucial for preserving thermally labile residues. The system's stainless steel luer lock hubs and 4-inch x 19-gauge stainless steel needles enable precise control of nitrogen flow, further enhancing evaporation consistency and sample integrity [5].

Implementation of the MICROVAP system into Dr. Vozka's laboratory workflow was straightforward due to its user-friendly design and minimal footprint. With a digital temperature controller and adjustable flow meter, the system allows for easy optimization based on sample and solvent properties. Its compact design conserves valuable hood space, a key benefit in space-constrained academic labs. Custom-designed sample blocks and inserts ensure optimal fit and efficient heat transfer for the specific glassware used in the fingerprint analysis workflow, further enhancing the processes efficiency and reproducibility [5].

Impact and Results

The integration of the 15 position MICROVAP into Dr. Vozka's fingerprint analysis workflow has yielded impressive improvements in both efficiency and analytical quality. Sample preparation time has been significantly reduced, allowing the research team to process more samples in less time and accelerating their progress toward developing a comprehensive fingerprint aging model. The batch processing capability has eliminated a major bottleneck in their workflow, enabling the analysis of larger sample sets that provide more robust statistical data for their aging models. This increased throughput has been achieved without sacrificing sample quality, thanks to the MICROVAP's precise control of evaporation parameters [4].

Sample-to-sample consistency has dramatically improved since implementing the MICROVAP system, resulting in more reliable detection of critical chemical markers in fingerprint residues. The research team has been able to successfully detect cholesterol metabolites across samples, although they noted that squalene was not consistently detected in all samples, highlighting the complexity of fingerprint composition analysis [3]. The controlled evaporation environment provided by the MICROVAP has minimized the selective loss of volatile compounds, ensuring that the chemical profiles obtained from GC×GC-TOFMS analysis accurately represent the original fingerprint composition [4]. This improvement in analytical fidelity is essential for developing reliable aging models that can withstand forensic scrutiny.

The safety aspects of the MICROVAP system have also benefited the laboratory environment, particularly when working with dichloromethane, a potential health hazard that requires careful handling. The enclosed evaporation process of the evaporator in the fume hood minimizes researcher exposure to solvent vapors, creating a safer working environment for researchers [5]. Additionally, the system's reliability has reduced the need for sample reprocessing, conserving valuable resources and maximizing the productivity of the laboratory. The consistent results obtained with the MICROVAP system have strengthened the validity of Dr. Vozka's research findings, positioning his team at the forefront of forensic fingerprint aging analysis [4].

Future Directions and Conclusion

Dr. Vozka's innovative application of GC×GC-TOFMS combined with the efficient sample preparation capabilities of the 15 position MICROVAP represents a significant advancement in forensic fingerprint analysis. The integration of this specialized evaporation technology has not only enhanced research productivity but also improved the quality and reliability of analytical results essential for developing accurate fingerprint aging models [4]. As the research continues, Dr. Vozka's team plans to refine their methods further, possibly expanding their analyte panel to include additional chemical markers that may provide more precise aging information [3]. The versatility of the MICROVAP system will support these evolving research needs, accommodating different sample types and volumes as the project progresses.

The successful implementation of the 15 position MICROVAP in Dr. Vozka's laboratory demonstrates the critical importance of appropriate sample preparation technologies in advanced analytical workflows. While sophisticated instrumentation like GC×GC-TOFMS receives much attention, the quality of data ultimately depends on careful sample processing throughout the analytical workflow. Organomation's MICROVAP has proven to be an essential component in bridging the gap between sample collection and high-resolution analysis, ensuring that the full potential of advanced chromatographic techniques can be reached. As Dr. Vozka continues to train the next generation of analytical chemists and forensic scientists at Cal State LA, the integration of professional-grade sample preparation equipment like the MICROVAP provides students with valuable hands-on experience that mirrors real-world laboratory practices, preparing them for successful careers in analytical science.

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