LQ-5Z Single-Parameter Acid-Base Concentration Analyzer

Overview

The LQ-5Z Single-Parameter Acid-Base Concentration Analyzer is a portable, field-deployable electrochemical instrument engineered for precise, real-time quantification of key alkaline and acidic species in aqueous process streams and environmental water samples. It operates on the potentiometric principle using ion-selective electrodes (ISEs) with optimized membrane formulations for selective response to hydroxide (OH⁻), ammonium (NH₄⁺), hydrogen ions (H⁺), and carbonate/bicarbonate systems—enabling direct measurement of total alkalinity or acidity without titration. Unlike multi-parameter platforms, the LQ-5Z is purpose-built for single-analyte monitoring in controlled industrial settings such as semiconductor wet benches (e.g., TMAH developer baths), electroplating rinse lines, boiler feedwater conditioning, and wastewater neutralization control. Its compact form factor, IP66-rated enclosure, and battery-powered operation support unattended deployment in harsh environments where continuous power supply is unavailable.

Key Features

• Electrode-based direct measurement: Utilizes calibrated 4C-type ISE probe (1 m cable) with integrated temperature sensor for automatic thermal compensation (0–50 °C)
• Single-analyte focus: Configurable per installation for one of five primary targets—TMAH (0.00–5.00 wt%), NaOH (0.00–3.00 wt%), Na₂CO₃ (0.0–10.0 wt%), NH₃/NH₄⁺ (0.0–2.00 wt%), or H₂SO₄ (0.0–2.00 wt%)
• Ruggedized design: IP66 ingress protection ensures reliable operation in humid, splash-prone, or outdoor installations
• Low-power architecture: Powered by three AAA batteries with auto-shutdown after 10 minutes of inactivity; typical battery life exceeds 200 hours of intermittent use
• Compact ergonomics: Host dimensions 75 mm (W) × 180 mm (D) × 38 mm (H); total system weight < 350 g including electrode
• Field-serviceable calibration: Two-point calibration routine supported via standard reference solutions traceable to NIST-certified materials

Sample Compatibility & Compliance

The LQ-5Z is validated for use with clarified, non-viscous aqueous matrices having conductivity between 100 µS/cm and 20 mS/cm and suspended solids < 50 mg/L. It is not suitable for highly turbid, oily, or polymer-laden effluents without pre-filtration. The analyzer complies with ISO 5667-3 for water sampling preservation and meets mechanical robustness requirements outlined in IEC 60529 (IP66). While not certified for intrinsic safety (ATEX/IECEx), its low-voltage operation (< 4.5 V DC) permits use in non-hazardous classified zones. Calibration protocols align with ASTM D1293 (pH of water) and ASTM D4192 (alkalinity titration) for method correlation verification.

Software & Data Management

The LQ-5Z operates as a standalone instrument with no embedded software stack or Bluetooth/Wi-Fi connectivity. All measurement data are displayed in real time on the integrated LCD and stored locally in non-volatile memory (up to 500 readings with timestamp and temperature). Data export requires manual transcription or optional RS-232 interface (available upon request). For regulated environments, users may integrate the LQ-5Z into existing SCADA or LIMS workflows via analog 4–20 mA output (add-on module). Audit trails, electronic signatures, and 21 CFR Part 11 compliance are not natively supported; however, paper-based calibration logs and measurement records satisfy GLP documentation requirements when maintained per internal SOPs.

Applications

• Semiconductor manufacturing: In-line monitoring of TMAH concentration in photoresist developer baths to maintain etch rate consistency
• Surface finishing: Real-time control of NaOH concentration in alkaline cleaning stages and H₂SO₄ in acid pickling tanks
• Power generation: Feedwater alkalinity tracking in condensate polishing systems to prevent copper alloy corrosion
• Municipal wastewater: Rapid assessment of lime dosing efficacy during pH adjustment prior to biological treatment
• Chemical distribution centers: Verification of bulk acid/alkali delivery concentrations before tank transfer

FAQ

What electrode types are compatible with the LQ-5Z?

The instrument is designed exclusively for the supplied 4C-type combination electrode—integrating pH, reference, temperature, and ion-selective sensing elements in a single robust housing.
Does the LQ-5Z support automatic temperature compensation?

Yes. An integrated Pt1000 RTD provides continuous temperature measurement from 0 °C to 50 °C, enabling automatic correction of electrode potential per the Nernst equation.
Can the LQ-5Z be used for seawater or brine analysis?

No. High ionic strength (> 50 g/L TDS) causes significant junction potential drift and membrane interference; use is limited to freshwater and low-salinity industrial process waters.
Is calibration traceable to national standards?

Calibration solutions must be prepared from NIST-traceable primary standards (e.g., potassium hydrogen phthalate, sodium tetraborate) following ISO/IEC 17025-compliant lab practices.
What maintenance intervals are recommended?

Electrode membrane cleaning with mild detergent every 48 hours of cumulative use; full recalibration required after electrode replacement, extended storage (>7 days), or exposure to extreme pH (13).