Cuticular hydrocarbon extraction and GC-FID analysis of sweat bees (Halictidae)

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Method synopsis

Extraction of cuticular compounds from individual bee specimens using n-pentane solvent followed by gas chromatographic analysis with flame ionization detection for chemical profile characterization. Includes compound identification via GC-MS and structural elucidation using mass spectral libraries.

Synthesized from method descriptions across 2 papers using this protocol.

Procedure from a recent peer-reviewed implementation

Steps below were extracted from the most recent peer-reviewed implementation of this protocol in the corpus — Chemical Variation among Castes, Female Life Stages and Populations of the Facultative Eusocial Sweat Bee <i> Halictus rubicundus </i> (Hymenoptera: Halictidae) (2021), Journal of Chemical Ecology. Implementations in other papers (listed below) may differ.

1. Chemical extraction
   Frozen females were individually rinsed for 15 s in 500 μl n-pentane (Uvasol, 99.5%, Merck, Germany) to extract cuticle surface compounds. All extracts were concentrated under a gentle stream of nitrogen to 25% of the original volume.
   Quantities: 500 μl n-pentane per individual, concentrated to 25% original volume, 10 μl n-octadecane (stock solution: 100 μg/ml in n-hexane) added as internal standardDuration: 15 seconds rinse time per specimenConditions: Gentle nitrogen stream for concentration
   Equipment: n-pentane (Uvasol, 99.5%, Merck, Germany), nitrogen stream, n-octadecane, n-hexane
2. Gas chromatography analysis
   Chemical analyses were performed on an Agilent 7820 A Series gas chromatograph equipped with a non-polar DB-5 MS capillary column (30 m × 0.25 mm inner diameter, J&W) and a flame ionization detector using hydrogen as carrier gas (constant flow, 2.0 ml/min). One microliter of each sample was injected splitless into the gas chromatograph (injector temperature: 310°C), operating at 50°C for 1 min, after which the split valve was opened, and the temperature was increased continuously by 10°C/min to a final temperature of 310°C.
   Quantities: 1 μl sample injection volumeDuration: Analysis time per sample from 50°C to 310°C with 10°C/min rampConditions: Injector temperature 310°C, hydrogen carrier gas at 2.0 ml/min constant flow, temperature program from 50°C to 310°C
   Agilent 7820 A Series gas chromatograph, DB-5 MS capillary column (30 m × 0.25 mm), flame ionization detector, hydrogen carrier gas

Typical Equipment

• n-pentane (Uvasol, 99.5%, Merck, Germany)
• nitrogen stream
• Agilent 7820 A Series gas chromatograph
• DB-5 MS capillary column
• flame ionization detector
• HP 6890 series gas chromatograph-mass spectrometer
• AMDIS 2.71 software
• NIST11 library
• solid-phase extraction equipment
• dimethyl disulfide (DMDS)

Output Measurements

• cuticular chemical profiles
• relative compound abundances
• compound identifications

Papers Using This Protocol (2)

Species Studied With This Protocol