Agilent NPD Blos bead G3434-60806

The Agilent NPD Blos bead (G3434-60806) is the heated bead assembly used as the ionization source in Agilent Nitrogen‑Phosphorus Detectors (NPD). In the NPD, column effluent is passed through a hydrogen–air plasma on the surface of the heated ceramic source (the bead); alkali ions coated on the bead surface uniquely facilitate ionization of nitrogen‑ and/or phosphorous‑containing organic compounds. The Blos bead is a specific bead type referenced by Agilent for installation and setup procedures in 7890 and 6890 GC systems and is used to establish the correct bead voltage and detector gas setpoints during detector commissioning and maintenance.

Key Features:

• Manufacturer part number: G3434-60806 (Blos bead)
• Typical ignition voltage for a new Blos bead: about 0.5 to 1.1 V
• Initial bead voltage recommendation: 0.0 to 0.5 V
• Recommended hydrogen detector flow with Blos bead: 1 to 3 mL/min
• Recommended air detector flow with Blos bead: 120 mL/min
• Recommended makeup gas flow with Blos bead: 1 to 20 mL/min

Advantages:

• Facilitates selective ionization of nitrogen‑ and phosphorus‑containing organic compounds through alkali‑coated bead surface (manufacturer stated).
• Lower required bead ignition voltage compared with ceramic beads, enabling initial bead setup at lower voltages (manufacturer data).
• Detector operating parameters (heater, gas flows, bead voltage) are defined by Agilent for stable baseline and reproducible NPD performance.