High-throughput seminal fluid identification by automated immunoaffinity mass spectrometry

Area of Science:

• Forensic Science
• Analytical Chemistry
• Biochemistry

Background:

• Traditional semen detection methods lack specificity and throughput for sexual assault cases.
• Protein mass spectrometry offers confirmatory results but is hindered by lengthy sample preparation and analysis.
• There is a need for faster, more accurate methods for seminal fluid identification in forensic investigations.

Purpose of the Study:

• To develop and validate a streamlined mass spectrometry assay for rapid and sensitive semen identification.
• To improve the efficiency and applicability of mass spectrometry in sexual assault investigations.
• To detect semen in challenging casework-type samples, including adulterated swabs.

Main Methods:

• Coupled a 60-minute rapid tryptic digestion with semenogelin-II peptide affinity purification using an automation platform.
• Employed a 3-minute targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.
• Utilized multiple reaction monitoring (MRM) mode on a triple quadrupole mass spectrometer for peptide detection.

Main Results:

• Successfully detected trace levels (0.0001 μl) of semen from various sample types.
• Demonstrated detection in cotton and vaginal swabs, including samples collected during menses or adulterated with lubricants.
• Achieved high-throughput analysis with a significantly reduced sample preparation and analysis time.

Conclusions:

• The developed mass spectrometry assay is a promising technique for high-throughput seminal fluid identification.
• This method offers a faster, more specific, and sensitive alternative to traditional forensic techniques.
• The streamlined approach enhances the practical applicability of mass spectrometry in sexual assault investigations.