From GROK

This auction is for 1 (one) fiber optic immersion probe (possibly model 661.609-UV) from Delphian Technology, specifically designed for the Rainbow Dissolution Monitor system (now associated with Pion Inc.). This is a UV-Vis spectroscopy probe used for in-situ real-time concentration monitoring in pharmaceutical dissolution testing, solubility studies, and related applications. The probe features a dual-fiber design (one for light transmission from a deuterium source, one for returning reflected light to a detector), with a reflective mirror at the tip to measure absorbance through the sample medium.
Key Specifications
Category
Details
Type
Straight dip/immersion fiber optic probe for UV-Vis absorbance measurements. Supports reflection mode with interchangeable tips. 
Optical Path Lengths
Interchangeable tips: Path length determines sensitivity and linear range for absorbance. Note: comes with 20mm tip installed - NO OTHER TIPS AVAILABLE
Wavelength Range
Optimal: 240–500 nm (Deuterium lamp source). UV cutoff around 240 nm due to transmission losses; consistent performance from 250–314 nm, with potential variability below 240 nm.
Absorbance Range
Up to 2 AU (absorbance units). Linear range: 0.05–1.5 AU across path lengths (deviation above 1.5 AU, e.g., ~11% at 2.0 AU for 20 mm path). Limit of Quantitation (LOQ): ~0.03 AU without excipients, ~0.05 AU with insoluble excipients.
Performance Metrics
- Baseline flatness: ≤0.002 AU (240–600 nm) - Noise: ≤0.002 AU at 600 nm - Stability: ≤0.002 AU at 270 nm - Stray light: ≤1% - Wavelength accuracy: ±1 nm (UV), ±2 nm (visible) - Minimum sampling interval: 2 seconds - Precision: RSD ~1–6% per probe, ~3.37% across multiple probes (tested with hydralazine HCl standards).
Materials and Design
- Optical components: Quartz or similar fibers for UV transmission; internal mirrors for light reflection. - Tip: Likely stainless steel or compatible material for immersion in dissolution media (e.g., acids, buffers). - Cable: Gray protective sheathing (PVC or silicone jacket), bifurcated design with two connectors (typically SMA or FC type; one often color-coded, e.g., blue for identification). - Compatibility: Resistant to common excipients; handles scattering from insoluble particles (e.g., starch, crospovidone) via baseline correction (e.g., at 380 nm). Avoids significant Tyndall scattering in tested conditions.
Dimensions
Probe-specific dimensions not explicitly detailed in sources, but compatible with standard dissolution vessels: - Fits USP Apparatus II (paddle stirrers at 50 rpm). - Recommended standardization containers: ≥25 mm internal diameter (e.g., 20-mL scintillation vials). - System-level dimensions (Rainbow R6 unit): 275 mm H × 177 mm W × 436 mm D. Probe cable length estimated at 2m.


Compatibility
Integrates with Rainbow R6 monitor and various dissolution testers (e.g., MicroDISS: 2–5 mL min. media; MiniDISS: 40–100 mL; MacroFLUX: 800–900 mL).