Unimicro Technologies UM 5800 Evaporative Light Scattering Detector (ELSD)

Overview

The Unimicro Technologies UM 5800 Evaporative Light Scattering Detector (ELSD) is a high-performance, benchtop-compatible detector engineered for universal detection of non-volatile and semi-volatile analytes in liquid chromatography workflows. Unlike UV-absorbing detectors, the UM 5800 operates on the principle of nebulization, solvent evaporation, and light scattering—making it especially valuable for compounds lacking chromophores, such as carbohydrates, lipids, glycosides, saponins, polymers, and thermally labile natural products. Its design complies fully with GB/T 33078–2016 (Chinese National Standard for ELSD performance evaluation) and supports method development aligned with ICH Q2(R2), USP , and FDA 21 CFR Part 11 requirements when integrated into validated HPLC systems. The detector is compatible with all major HPLC platforms—including Agilent, Waters, Shimadzu, and Thermo Fisher—via standard analog (0–1 V DC) and digital (RS-232) interfaces.

Key Features

• Optimized dual-stage evaporation chamber enabling stable operation across ambient-to-130 °C temperature range—ideal for both low-boiling solvents (e.g., acetonitrile/water) and high-boiling mobile phases (e.g., THF or chloroform-based systems).
• High-sensitivity optical module featuring a 650 nm semiconductor laser and low-noise photomultiplier tube (PMT), delivering baseline noise <0.03 mV and drift <0.03 mV/h under continuous operation.
• Intelligent gas management system: real-time monitoring of carrier gas pressure (2–5 bar) and flow (1–4 L/min) with ±0.01 bar resolution and ≤1% accuracy—ensuring consistent droplet size distribution and signal reproducibility.
• Compact mechanical architecture (460 × 330 × 220 mm) with EMI-shielded internal layout, minimizing electromagnetic interference and enhancing long-term signal stability.
• 7-inch full-color capacitive touchscreen interface supporting intuitive parameter configuration, real-time status visualization, and built-in alarm logic for temperature, gas pressure, and flow deviations.
• Modular nebulizer assembly designed for rapid disassembly and cleaning—reducing downtime and preventing residue buildup that causes baseline instability or peak tailing.

Sample Compatibility & Compliance

The UM 5800 detects any analyte with volatility lower than the mobile phase, including but not limited to monosaccharides, oligosaccharides, phospholipids, fatty acid esters, amino acid derivatives, herbal saponins, and synthetic polymers. It has been widely adopted in Chinese Pharmacopoeia (ChP) monographs for quality control of traditional Chinese medicines (TCMs), where UV-invisible active constituents—such as ginsenosides, astragalosides, and puerarin—are quantified without derivatization. The instrument meets ISO/IEC 17025 general requirements for testing laboratories and supports GLP-compliant data integrity through audit-trail-enabled software integration (when paired with compliant CDS platforms). Its gradient-compatible operation eliminates solvent front interference, enabling robust quantitation even in complex multi-step elution methods.

Software & Data Management

While the UM 5800 operates autonomously via its embedded firmware and touchscreen UI, it is fully interoperable with third-party chromatography data systems (CDS) via RS-232 serial communication. Analog 0–1 V DC output allows direct connection to legacy integrators and modern acquisition modules. When integrated into regulated environments, the detector’s real-time parameter logging—temperature setpoint, actual chamber temperature, gas pressure, flow rate, and alarm events—can be synchronized with CDS audit trails. Firmware supports configurable sampling rates (up to 20 Hz), adjustable PMT gain, and user-defined integration baselines—facilitating method transfer and cross-platform validation per ICH guidelines.

Applications

• Quantitative analysis of polysaccharides in botanical extracts and functional foods.
• Stability-indicating assays for degradation-prone APIs without UV chromophores.
• Residual solvent and excipient profiling in biopolymer formulations (e.g., PLGA microspheres).
• Method development for lipidomics workflows requiring broad dynamic range (0.1–30 μg) and low-ng detection limits.
• QC release testing of TCM injections and oral liquids per ChP Chapter 0421 (ELSD-based assay methods).
• Support of forced degradation studies under acidic, basic, oxidative, and thermal stress conditions.

FAQ

Is the UM 5800 compatible with UHPLC systems?
Yes—the detector accepts flow rates from 10 μL/min to 3 mL/min and features low-volume nebulization geometry optimized for narrow-bore and capillary columns.
What carrier gases are supported?
Nitrogen (recommended for lowest baseline noise) and oil-free compressed air are both validated; gas purity ≥99.995% N₂ is advised for trace-level applications.
Does the UM 5800 support 21 CFR Part 11 compliance?
The hardware itself does not include electronic signatures or role-based access control—but when connected to a 21 CFR Part 11-compliant CDS (e.g., Empower, Chromeleon, or OpenLab), all operational parameters and alarms are captured in the system’s secure audit trail.
Can the evaporation temperature be ramped during a run?
No—the UM 5800 maintains a fixed evaporation temperature per method; however, multiple methods with different temperature setpoints can be sequenced via external CDS control.
How often does the nebulizer require maintenance?
Under normal use with HPLC-grade solvents, visual inspection and ultrasonic cleaning are recommended every 200–300 injections; no consumable parts require scheduled replacement.