ShengAohua SH-50L Portable Residual Chlorine and Total Chlorine Analyzer

Overview

The ShengAohua SH-50L Portable Residual Chlorine and Total Chlorine Analyzer is a field-deployable spectrophotometric instrument engineered for rapid, on-site quantification of free residual chlorine and total chlorine in drinking water, treated wastewater, swimming pools, cooling towers, and distribution system samples. It implements the standardized N,N-diethyl-p-phenylenediamine (DPD) colorimetric method—fully aligned with ISO 7393-2:2018, EPA Method 334.0, and GB/T 5750.11–2023—where chlorine species oxidize DPD to form a stable pink-colored quinoneimine dye, measurable at 515 nm. Unlike benchtop analyzers requiring calibration curves or reference standards, the SH-50L employs pre-programmed, factory-validated calibration algorithms embedded in its microcontroller, enabling direct concentration readout without manual standardization. Its optical path is stabilized by temperature-compensated LED light source and precision photodiode detection, ensuring consistent absorbance linearity across ambient conditions ranging from 5 °C to 40 °C.

Key Features

• True portable architecture: Compact (220 × 120 × 85 mm), lightweight (≤0.8 kg), and IP65-rated for dust and splash resistance—designed for daily field use by utility technicians and environmental inspectors.
• Integrated dual-parameter measurement: Simultaneous or sequential analysis of residual chlorine (free Cl₂) and total chlorine (free + combined chlorine) using dedicated DPD reagent protocols per ISO 7393-2.
• Optical stability maintained at ≤ ±0.005 A over 20 minutes—critical for minimizing drift during extended monitoring campaigns or multi-sample batch analysis.
• High-resolution LCD with backlight: Enables legible readings under low-light conditions (e.g., underground valve chambers, nighttime sampling); intuitive Chinese-language UI with tactile membrane keypad eliminates reliance on touchscreens in wet environments.
• Cuvette-based photometry: Uses standardized 10-mm pathlength glass cuvettes—compatible with ASTM D1253-22 sample handling practices and eliminating need for disposable vials or complex flow cells.
• Dual-power operation: Powered by high-capacity rechargeable lithium-ion battery supporting ≥160 consecutive measurements per charge (~7 days typical field duty); includes universal AC/DC adapter for lab or vehicle charging.

Sample Compatibility & Compliance

The SH-50L accepts raw, filtered, or clarified aqueous samples with turbidity < 5 NTU and suspended solids < 10 mg/L—consistent with US EPA guidance for chlorine residual testing. It complies with regulatory data integrity requirements through built-in time-stamped measurement logging (RTC clock with ±2 s/month accuracy) and non-volatile microSD card storage (≥10,000 records). All firmware and calibration data are write-protected; user-modifiable parameters (e.g., date/time, unit selection) require administrator-level password access. While not certified for GLP/GMP production environments, its operational traceability supports ISO/IEC 17025-compliant laboratories conducting routine compliance verification under drinking water directives (e.g., EU Directive 98/83/EC, US Safe Drinking Water Act).

Software & Data Management

Measurements are automatically timestamped and stored with sample ID, operator code, and parameter type. The internal memory retains full audit trail metadata—including battery voltage, ambient temperature, and optical zero check status—for each record. Data export is supported via USB 2.0 interface to Windows-compatible PCs; exported CSV files include columns for Date, Time, Sample_ID, Parameter, Concentration (mg/L), Unit, and QC Flag (e.g., “Low Signal”, “Overrange”). Firmware updates are delivered via signed binary packages verified by SHA-256 checksum—ensuring integrity against unauthorized modification. No cloud connectivity or remote telemetry is implemented, preserving data sovereignty for municipal and industrial users subject to local data residency regulations.

Applications

• Drinking water treatment plants: Verification of post-disinfection residual levels at entry points, booster stations, and endpoint taps.
• Municipal wastewater facilities: Monitoring chlorine contact tank effluent and dechlorination efficiency prior to discharge.
• Swimming pool & spa management: Routine compliance checks per WHO Guidelines for Safe Recreational Water Environments and national health codes.
• Pharmaceutical water systems: Qualification of purified water (PW) and water-for-injection (WFI) distribution loops where chlorine residuals must be controlled below 0.1 mg/L.
• Field education & research: Used in university environmental science labs for student-led water quality surveys and method validation studies.

FAQ

What reagents are required for operation?
DPD Powder Reagent Sets (Part No. SH-DPD-01) and Buffer Tablets (Part No. SH-BUF-02), supplied separately. Each kit supports ≥200 tests.
Is calibration verification required before each use?
No. Factory calibration is retained for ≥12 months under normal storage; users perform only a blank verification (deionized water) before first measurement of each session.
Can the instrument measure chlorine dioxide (ClO₂) simultaneously?
No. The SH-50L is configured exclusively for residual and total chlorine per DPD Method 4500-Cl G. ClO₂ requires separate amperometric or Lissamine Green B methods.
How is measurement uncertainty reported?
Total error budget includes ±5% accuracy (traceable to NIST SRM 2822 chlorine standard), ±0.001 mg/L resolution, and ±0.005 A photometric noise—combined per ISO/IEC Guide 98-3 (GUM).
Does the device support regulatory reporting formats?
Yes. Exported CSV files conform to EPA Storage and Retrieval Format (SARF) conventions and are compatible with LIMS platforms such as LabWare LIMS and Thermo Fisher SampleManager.