Ruixin SZ-SJPH2 Portable pH Colorimetric Analyzer

Overview

The Ruixin SZ-SJPH2 Portable pH Colorimetric Analyzer is a dedicated, field-deployable instrument engineered for rapid, on-site quantification of pH in potable water and municipal drinking water supplies. Unlike conventional electrochemical pH meters, the SZ-SJPH2 employs standardized colorimetric methodology based on acid-base indicator chemistry—specifically optimized for the bromothymol blue or phenol red reaction system—coupled with precise photometric detection across the visible spectrum (380–630 nm). This optical approach eliminates electrode calibration drift, junction clogging, and temperature-dependent potential errors common in glass-electrode systems, making it especially suitable for routine surveillance where operator training, environmental robustness, and assay consistency are critical. The analyzer complies with fundamental principles outlined in ISO 10523 (Water quality — Determination of pH) and supports method validation workflows aligned with national food safety monitoring programs (e.g., China’s GB 5749-2022 for drinking water quality).

Key Features

• Compact aluminum alloy chassis with integrated ergonomic handle—designed for repeated field transport and operation under ambient lighting conditions.
• 4.5-inch high-resolution color TFT touchscreen with full Chinese GUI; supports touch-pen input and intelligent Pinyin-based Chinese character entry for direct annotation of sample IDs, locations, and operator notes.
• Dual photometric display modes: absorbance (0.000–4.000 AU, resolution 0.001) and transmittance (0.00–100.00%, resolution 0.01%), both traceable to NIST-traceable neutral density filters.
• Built-in thermal line printer enables immediate hardcopy generation of test reports—including date/time stamp, measured value, calibration ID, and operator signature field.
• Onboard memory stores ≥ 500 test records with timestamp, sample ID, and calibration curve metadata; recall function supports chronological or alphanumeric search.
• Multi-source power architecture: operates via AC 220 V mains, USB 5 V DC, or rechargeable lithium-ion battery (≥ 8 hours continuous use at 25°C).
• Optical path stability ≤ 0.3% over 3 minutes—verified per ASTM E275 for spectrophotometer baseline drift assessment.

Sample Compatibility & Compliance

The SZ-SJPH2 is configured exclusively for aqueous liquid samples in standard 10 mm pathlength cuvettes (supplied). It is validated for use with EPA-approved colorimetric pH reagent kits (e.g., Hach Method 8079) and compatible third-party indicators conforming to APHA Standard Methods 4500-H⁺ B. While not intended for turbid or highly colored matrices without pretreatment, the instrument meets functional requirements for Category I field screening under China’s National Food Safety Risk Monitoring Plan (NFSP). Its optical repeatability (≤0.2%) satisfies internal QC thresholds defined in ISO/IEC 17025-accredited laboratories for non-certified screening tools.

Software & Data Management

Data export is supported via RS232 serial interface (9600 bps, 8N1) and USB 2.0 host port, enabling direct transfer to LIMS or Excel-compatible CSV files. Firmware includes audit trail logging for calibration events, user logins, and result modifications—structured to support GLP-aligned documentation practices. No cloud connectivity or proprietary software installation is required; all configuration and report formatting occur locally on-device. Firmware updates are delivered via USB flash drive and include version-signed integrity verification.

Applications

• Routine verification of treated drinking water at distribution points, wells, and emergency response sites.
• Pre-screening of source water prior to advanced treatment (e.g., coagulation, disinfection) in small-scale utilities.
• Field validation of pH adjustment during food processing water recirculation loops (e.g., dairy CIP rinse monitoring).
• Educational use in food science and environmental health curricula for teaching colorimetric assay fundamentals.
• Supplemental verification tool in ISO 22000-certified facilities where electrochemical sensor redundancy is mandated.

FAQ

Is the SZ-SJPH2 compliant with FDA or EU regulatory frameworks for food safety testing?
The instrument itself is not a regulated medical device or IVD; however, its measurement methodology aligns with AOAC Official Method 973.44 (colorimetric pH) and supports data integrity practices referenced in FDA 21 CFR Part 11 when used within documented SOPs.
Can it measure pH outside the 5.8–9.0 range?
No—the optical detection system and preloaded calibration curves are validated solely for that interval. Samples falling outside require dilution or alternative methodology.
Does it require daily calibration with buffer solutions?
Yes—two-point calibration (pH 7.00 and pH 4.01 or 10.01) is required before each batch of analyses, using NIST-traceable certified buffers.
Is the thermal printer compatible with standard label stock?
It accepts only 57 mm wide direct-thermal paper rolls (no ribbon); custom labeling requires external print-and-apply integration.
What is the warranty and service support structure outside China?
Ruixin provides 12-month limited hardware warranty; international technical support is delivered remotely via authorized regional distributors with local language documentation.