Ruixin SP-Z2 Protein Analyzer for Milk Powder and Dairy Products

Overview

The Ruixin SP-Z2 Protein Analyzer is a dedicated photometric instrument engineered for rapid, on-site quantification of total protein content in milk powder and processed dairy products. It operates on the principle of spectrophotometric absorbance measurement at a fixed wavelength of 540 nm—optimized for the biuret or Lowry-type colorimetric reaction commonly employed in dairy protein analysis. Unlike general-purpose spectrophotometers, the SP-Z2 integrates assay-specific optical path calibration, reagent-compatible cuvette geometry, and pre-validated calibration algorithms aligned with national standard methods (e.g., GB 5009.5–2016 for protein determination in food). Designed for compliance-driven quality control environments—including infant formula manufacturing facilities, dairy processing QA labs, and third-party food safety inspection agencies—the SP-Z2 delivers traceable, repeatable results without requiring operator spectroscopy expertise.

Key Features

• Integrated optical self-calibration system: Eliminates manual zeroing and 100% transmittance adjustment; performs automatic baseline correction at power-on.
• Dedicated 4.3-inch high-resolution TFT color touchscreen with full Chinese GUI: Enables intuitive navigation, real-time absorbance/transmittance display, and direct Chinese character input via on-screen keyboard or stylus.
• Embedded thermal printer: Generates audit-ready hardcopy reports containing protein concentration (g/100g), sample name (Chinese/English), test date/time, analyst ID, and testing unit—fully traceable per GLP documentation requirements.
• Triple-power operation: Supports continuous field use via built-in rechargeable Li-ion battery (≥6 hrs runtime), AC 220 V mains, or DC 5 V external supply—ideal for mobile labs and warehouse inspections.
• Dual photometric readout: Simultaneously displays absorbance (0.000–4.000 AU, resolution 0.001) and transmittance (0.00–100.00%, resolution 0.01%), enabling method flexibility beyond protein assays (e.g., lactose or ash-related colorimetric tests).
• Data integrity architecture: Automatic result logging with timestamped storage (≥1,000 records); USB and RS-232 interfaces support secure data export to LIMS or centralized QA databases.

Sample Compatibility & Compliance

The SP-Z2 is validated exclusively for homogenized liquid dairy samples (reconstituted milk powder, UHT milk, yogurt supernatants) and dry powder matrices following standardized sample preparation per GB/T 22388–2008 and ISO 8968-1:2014. Its 540 nm optical path is optimized for the purple complex formed between peptide bonds and copper ions under alkaline conditions—ensuring minimal interference from common dairy excipients (e.g., lactose, casein hydrolysates, mineral fortificants). Instrument performance meets key metrological criteria specified in JJG 178–2015 (Chinese National Verification Regulation for Visible Spectrophotometers): photometric repeatability ≤0.2% CV, photometric stability ≤0.3% drift over 3 minutes, and transmittance accuracy ±2.0%. While not FDA 21 CFR Part 11–certified out-of-box, its audit trail functionality (timestamped printouts + exported CSV logs) supports alignment with GMP/GLP documentation practices during internal validation.

Software & Data Management

The SP-Z2 embeds firmware v3.2 with non-volatile memory for method storage, calibration curve retention, and user-defined sample naming. All measurements are automatically tagged with date, time, operator ID, and channel-specific metadata. Data export via USB mass storage mode generates comma-separated value (CSV) files compatible with Microsoft Excel, Minitab, or laboratory information management systems (LIMS). RS-232 serial output enables integration into automated QC dashboards using Modbus RTU protocol. No proprietary software installation is required—raw data files contain no encryption or vendor lock-in, facilitating third-party statistical process control (SPC) analysis.

Applications

• Routine verification of protein labeling compliance in infant formula production lines.
• On-site screening of incoming raw milk powder shipments at receiving docks.
• Batch release testing for whey protein concentrates and caseinates.
• Field-based surveillance by municipal food safety bureaus during market inspections.
• Educational use in food science laboratories for teaching standardized colorimetric assay principles.

FAQ

What protein quantification method does the SP-Z2 implement?
It uses a fixed-wavelength (540 nm) colorimetric assay based on the biuret reaction principle, calibrated against Kjeldahl reference values per GB 5009.5–2016.
Can the SP-Z2 measure other analytes besides protein?
No—it is a single-analyte instrument with optical and algorithmic optimization exclusively for dairy protein. Its 540 nm channel is not configurable for alternate wavelengths.
Is external calibration required before each use?
No. The integrated optical self-correction system performs automatic dark-current and reference compensation at startup, eliminating manual zero/100% adjustments.
How is data traceability ensured for regulatory audits?
Each printed report includes sample ID, concentration, analyst name, date/time stamp, and instrument serial number; exported CSV files retain identical metadata and are human-readable without proprietary viewers.
What sample preparation is needed prior to analysis?
Samples must be homogenized and subjected to standardized alkaline digestion and reagent addition per GB/T 22388–2008; the SP-Z2 measures only the final colored reaction mixture in 10-mm pathlength cuvettes.