DiamondPure Steel/Magnetic Screw Cap for 20mL Headspace Vials, 18mm Finish, 1.3mm PTFE/Silicone Septa, 100/Pack
The Globe Scientific DiamondPure Steel/Magnetic Screw Cap for 20mL Headspace Vials delivers a secure, CTC-compatible seal for automated headspace GC workflows. Engineered with an 18mm finish and a bonded PTFE/silicone septum, these caps suit residual solvent analysis, volatile organic compound (VOC) screening, and forensic toxicology sampling where reliable sealing prevents analyte loss.
Technical Specifications
| Product Type | Steel/Magnetic Screw Cap, 18mm Finish |
| Volume/Size | For 20mL headspace vials, 18mm finish |
| Material | Steel/magnetic cap body |
| Closure/Cap | Magnetic screw cap; 1.3mm bonded PTFE/silicone septum |
| Graduation | Not applicable |
| Sterility | Non-sterile |
| Pack Size | 100 caps/pack |
Available Colors
| Red — Red PTFE/White Silicone — Bag of 100 | 9050000CAP-SM-RW | $102.00 |
| White — White PTFE/Blue Silicone — Bag of 100 | 9050000CAP-SM-WB | $108.00 |
Applications
- Static headspace GC analysis of volatile organic compounds
- USP <467> residual solvent testing in pharmaceutical QC
- Blood alcohol and forensic toxicology headspace sampling
- Environmental screening of trace volatiles in water and soil extracts
- Automated sampling on CTC/PAL magnetic transport autosamplers
- Food and beverage flavor and off-odor volatile profiling
Chemical Resistance
| Aqueous buffers | Excellent |
| Dilute acids | Excellent (PTFE-facing) |
| Dilute bases | Excellent (PTFE-facing) |
| Alcohols | Excellent |
| Acetonitrile | Good |
| Aromatic solvents | Good (limit septum contact time) |
| Chlorinated solvents | Good (limit septum contact time) |
Quality & Procurement
Purchase through labsupplies.com, an authorized Globe Scientific dealer shipping from US inventory. Each pack carries a lot number, supporting traceability for CAP-, CLIA-, and ISO 15189-accredited laboratories. Institutional and grant-funded tiered pricing is available — contact our procurement team for volume quotes.
Frequently Asked Questions
Are these caps compatible with CTC/PAL autosampler systems?
Yes. The magnetic steel cap body is designed for CTC-compatible magnetic transport heads, enabling reliable pickup and placement on automated headspace platforms.
Which septum orientation faces the sample?
The PTFE layer faces the sample to provide chemical inertness, while the silicone layer offers resealing and puncture resilience after needle penetration.
What vial finish do these caps fit?
They are sized for the 18mm finish standard on 20mL headspace vials commonly used in static headspace GC analysis.
What is the difference between the red and white versions?
Both share the steel/magnetic body and 1.3mm septum. The red cap uses a red PTFE/white silicone septum; the white cap uses a white PTFE/blue silicone septum for color-coded sample tracking.