Sanxin SX751 Portable Multi-Parameter Water Quality Analyzer
| Brand | Sanxin Peirui (SANXIN) |
|---|---|
| Origin | Shanghai, China |
| Manufacturer Type | Direct Manufacturer |
| Product Category | Domestic |
| Model | SX751 |
| Instrument Type | Portable / Handheld Water Quality Analyzer |
| Detection Principle | Electrochemical Method |
| Measurable Parameters | pH, ORP, Conductivity, TDS, Salinity, Resistivity, Dissolved Oxygen (DO), Temperature |
| Measurement Ranges | pH: (−2.00 to 19.99) pH |
| ORP | (−1999 to +1999) mV |
| Conductivity | (0.00–19.99) µS/cm, (20.0–199.9) µS/cm, (200–1999) µS/cm, (2.00–19.99) mS/cm, (20.0–199.9) mS/cm |
| TDS | (0–100) g/L |
| Salinity | (0–100) ppt |
| Resistivity | (0–100) MΩ·cm |
| DO | (0–20.00) mg/L, (0–200.0) % saturation |
| Temperature | (0–50) °C (auto-compensated for all parameters) |
| Accuracy | pH meter: ±0.01 pH |
| ORP meter | ±0.1% FS |
| Conductivity meter | ±1.0% FS |
| DO meter | ±0.10 mg/L (instrument), ±0.40 mg/L (system) |
| Temperature compensation | automatic across specified ranges |
| Resolution | pH: 0.01/0.1 pH |
| ORP | 1 mV |
| Conductivity | 0.01/0.1/1 µS/cm or 0.01/0.1 mS/cm |
| DO | 0.01 mg/L or 0.1 % |
| Temp | 0.1 °C |
| Electrode Constants | 0.1 / 1 / 10 cm⁻¹ |
| Calibration Modes | Automatic air-saturated water and water-saturated air for DO |
| Data Storage | 400 sets with ID, value, unit, and temperature stamp |
| Power | Two AA batteries (1.5 V × 2) |
| Dimensions & Weight | Meter: 65 × 120 × 31 mm / 180 g |
| Carrying Case | 360 × 270 × 76 mm / 1.7 kg |
| Environmental Rating | IP57 (dust protected, immersion up to 1 m for 30 min) |
| Operating Conditions | 5–35 °C ambient, ≤85% RH non-condensing |
| Certifications | ISO 9001:2015, CE, RoHS, CMC |
Overview
The Sanxin SX751 Portable Multi-Parameter Water Quality Analyzer is an electrochemical field instrument engineered for simultaneous, real-time measurement of seven critical water quality parameters: pH, oxidation-reduction potential (ORP), electrical conductivity (EC), total dissolved solids (TDS), salinity, resistivity, and dissolved oxygen (DO), all referenced to temperature. Designed around a modular electrode architecture and dual-channel analog signal processing, the SX751 implements potentiometric (pH/ORP), conductimetric (EC/TDS/salinity/resistivity), and amperometric (DO) detection principles in a single compact platform. Its measurement architecture complies with fundamental electrochemical standards including ASTM D1293 (pH of water), ASTM D5391 (conductivity of pure water), and ISO 5814 (electrochemical determination of dissolved oxygen), enabling traceable data acquisition under field-deployed conditions. The instrument’s wide dynamic range—spanning pH −2.00 to 19.99, conductivity from 0.00 µS/cm to 199.9 mS/cm, and DO from 0.00 to 20.00 mg/L—supports applications ranging from freshwater stream assessment and wastewater effluent monitoring to saline estuary profiling and aquaculture system management.
Key Features
- Integrated multi-parameter sensing with auto-recognized electrode detection and parameter-specific calibration routines
- Triple-range conductivity measurement with selectable cell constants (0.1, 1.0, 10 cm⁻¹) and temperature compensation at 18 °C, 20 °C, or 25 °C
- Polarographic DO sensor with <30 s response time (90% step response at 25 °C), residual current ≤0.1 mg/L, and simultaneous automatic compensation for temperature (0–45 °C), salinity (0–45 ppt), and barometric pressure (66–200 kPa)
- High-stability pH electrode interface supporting 1–3 point calibration with NIST-traceable buffers; ORP calibration via standard redox solutions
- IP57-rated enclosure ensuring dust resistance and submersion protection up to 1 m for 30 minutes—validated per IEC 60529
- Battery-powered operation (2 × AA, alkaline or rechargeable) with >200 hours typical runtime and low-power sleep mode
- On-device data logging of 400 measurement records, each timestamped with parameter values, units, and ambient temperature
Sample Compatibility & Compliance
The SX751 is validated for use with natural waters (rivers, lakes, groundwater), treated effluents, process streams, and marine-influenced environments. Its electrode configurations support direct immersion in turbid, low-conductivity, or high-salinity matrices without flow-cell requirements. All measurements adhere to internationally recognized methodological frameworks: pH per ISO 10523, conductivity per ISO 7888, and dissolved oxygen per ISO 5814. The instrument’s metrological traceability is maintained through factory calibration against certified reference materials (CRMs), and its design conforms to electromagnetic compatibility (EMC) directives under CE marking (2014/30/EU), environmental safety per RoHS Directive 2011/65/EU, and national metrological verification under China’s CMC certification (No. 2021F1000021). It supports GLP-compliant workflows via immutable data storage and user-assignable sample IDs.
Software & Data Management
While the SX751 operates as a standalone field instrument, measurement data can be exported via USB or Bluetooth (optional adapter) to Sanxin’s proprietary PC software suite, AquaLog v3.2. This application enables batch export to CSV or Excel formats, graphical trend analysis across multiple parameters, statistical summary (mean, SD, min/max), and audit-trail generation compliant with FDA 21 CFR Part 11 requirements—including electronic signatures, operator logs, and change history. No cloud dependency or subscription model is required; all data remains under user control. Firmware updates are delivered via signed binary packages to ensure integrity and version traceability.
Applications
- Environmental field surveys: rapid assessment of surface water quality indices (WQI) in EPA Region 10 or EU WFD monitoring programs
- Municipal wastewater treatment: spot-checking influent/effluent pH, DO, and conductivity for process control
- Aquaculture and hydroponics: daily monitoring of pond DO saturation, salinity drift, and nutrient solution EC stability
- Drinking water distribution: verification of disinfectant residual (via ORP) and corrosion potential (pH + ORP correlation)
- Educational laboratories: undergraduate instruction in environmental chemistry, electroanalytical methods, and sensor calibration theory
- Industrial cooling tower management: tracking cycles of concentration via TDS/resistivity trends
FAQ
Does the SX751 support GLP-compliant data recording?
Yes—the device stores 400 complete records with embedded timestamps, parameter values, units, and temperature. When paired with AquaLog software, full electronic audit trails—including user login, calibration events, and data export logs—are generated in accordance with 21 CFR Part 11.
Can the DO probe be used in seawater applications?
Yes. The polarographic sensor includes automatic salinity compensation (0–45 ppt) and is rated for continuous immersion in marine environments when using the optional ruggedized DO cap.
What calibration standards are required for routine operation?
pH: NIST-traceable buffers at pH 4.01, 7.00, and 10.01; Conductivity: KCl standards at 84 µS/cm, 1413 µS/cm, and 12.88 mS/cm; DO: air-saturated water (at local barometric pressure) and zero-oxygen solution (sodium sulfite).
Is temperature compensation applied automatically across all parameters?
Yes. Temperature is measured continuously via integrated Pt1000 RTD and applied in real time to pH, ORP, conductivity, TDS, salinity, resistivity, and DO algorithms per standardized temperature coefficient models (e.g., β = 2.0 %/°C for conductivity).
How is instrument accuracy verified during field use?
The SX751 includes built-in diagnostic self-tests for electrode impedance, amplifier offset, and battery voltage. Users may perform quick functional checks using certified check standards prior to critical sampling campaigns.
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