Hach XOS Total Lead and Total Arsenic Online Analyzer

Overview

The Hach XOS Total Lead and Total Arsenic Online Analyzer is an industrial-grade, continuous-monitoring instrument engineered for real-time quantification of dissolved and particulate-bound lead (Pb) and arsenic (As) in raw water, treated drinking water, wastewater effluent, and industrial process streams. Unlike conventional wet-chemistry or electrochemical analyzers, the XOS employs monochromatic wavelength-dispersive X-ray fluorescence (MWDXRF) — a solid-state, reagent-free elemental analysis technique. In MWDXRF, a low-power (50 W), air-cooled X-ray tube generates broadband radiation, which is then spectrally filtered and focused via a doubly curved crystal (DCC) mirror to produce a highly intense, monoenergetic excitation beam. This monochromatic irradiation selectively excites inner-shell electrons of Pb and As atoms in the sample matrix, inducing characteristic secondary X-ray fluorescence emission. The emitted photons are collected and resolved by a high-resolution silicon drift detector (SDD), enabling direct, matrix-robust quantification without acid digestion, chemical reduction, or electrode calibration. The absence of consumables, zero reagent waste, and immunity to turbidity, color, or organic interference make the XOS uniquely suited for unattended, long-term deployment in regulatory-compliant water monitoring networks.

Key Features

• Monochromatic excitation via DCC optics delivers superior signal-to-noise ratio (SNR) and minimizes spectral background, enabling sub-ppb detection limits without high-voltage or vacuum requirements.
• Dual-element capability: Simultaneous or sequential quantification of total Pb (LOD: 0.005 mg/L) and total As (LOD: 0.001 mg/L) within a single platform.
• True online operation: Integrated flow cell accepts pressurized, filtered water samples (5–50 psi) at 50–80 mL/min; no manual sampling or offline digestion required.
• Adaptive measurement timing: Intelligent algorithm selects optimal acquisition time (10–50 min) based on real-time signal intensity — ensuring precision across wide dynamic ranges (Pb: 0.15–10 mg/L; As: 0.1–5 mg/L).
• Low-maintenance architecture: Air-cooled 50 kV/1 mA X-ray tube with field-replaceable design; no coolant, oil, or cryogenic cooling needed.
• Industrial-grade interface: 7-inch capacitive touchscreen with intuitive navigation, multilingual support, and embedded diagnostics.
• Robust electrical compliance: Dual-input AC power handling (90–264 VAC, 47–63 Hz), integrated 4 A circuit breaker with 30 mA RCD protection, and IP53-rated enclosure for semi-outdoor installation.
• Standardized digital integration: RS-485 Modbus RTU interface supports seamless connectivity with SCADA, DCS, and LIMS systems for automated data logging and alarm relay control (2-channel, 220 V, 3 A).

Sample Compatibility & Compliance

The XOS analyzer is validated for use with potable water, surface water, groundwater, municipal wastewater, and industrial discharge streams meeting ISO 5667-3 (water sampling) and ASTM D5173 (trace metal analysis in water) preconditions. When paired with the optional CYQ-008X heavy-metal-specific pretreatment unit — featuring 40 µm precision filtration, pressure-regulated delivery (5–20 psi), and automated backflush cleaning — the system ensures representative, particle-free sample introduction compliant with EPA Method 200.8 and ISO 11885 requirements for total recoverable metals. All hardware and firmware conform to IEC 61326-1 (EMC for laboratory equipment), IEC 61000-4 series (immunity testing), and RoHS Directive 2011/65/EU. Data integrity adheres to ALCOA+ principles; audit trail functionality, electronic signature support, and user-access-level controls align with FDA 21 CFR Part 11 readiness for regulated utilities operating under GLP/GMP frameworks.

Software & Data Management

The embedded firmware provides full-cycle instrument control, including automatic warm-up stabilization, background subtraction, peak deconvolution, and multi-point calibration management. Quantitative results are reported in mg/L (ppm) with associated confidence intervals derived from Poisson-count statistics. Raw spectral data (energy channel vs. counts) and processed spectra are exportable via USB or Modbus register mapping. Optional Hach Insight™ Cloud Connect enables remote firmware updates, predictive maintenance alerts, and centralized fleet monitoring across distributed sites. All measurement records include timestamp, operator ID, calibration status, and environmental metadata (temperature, humidity, voltage), satisfying traceability requirements per ISO/IEC 17025:2017 Clause 7.7.

Applications

• Drinking water treatment plants: Continuous compliance monitoring for Pb and As against WHO guidelines (10 µg/L As, 10 µg/L Pb) and U.S. EPA Lead and Copper Rule (LCR) action levels.
• Municipal wastewater treatment facilities: Effluent monitoring per NPDES permit conditions and EU Urban Wastewater Treatment Directive Annex I limits.
• Industrial pretreatment systems: Real-time tracking of metal loading from electroplating, semiconductor fabrication, or mining-affected influents.
• Environmental monitoring stations: Long-term trend analysis in rivers, reservoirs, and aquifers impacted by legacy contamination or geogenic As mobilization.
• Regulatory verification: Reference-grade validation tool for cross-checking ICP-MS or AAS lab results in QA/QC programs.

FAQ

Does the XOS require acid digestion or sample preservation prior to analysis?
No. The MWDXRF method measures total recoverable Pb and As directly in unacidified, unpreserved water samples — eliminating digestion-related errors and labor-intensive preparation.
How does the XOS handle suspended solids or turbid samples?
When used with the CYQ-008X pretreatment module, the system delivers consistently filtered (<40 µm), pressure-stabilized samples. MWDXRF itself is inherently insensitive to optical interferences such as color or turbidity.
Is the instrument suitable for unattended operation in remote locations?
Yes. With its wide-input AC power range, low power draw (400 VA), IP53 rating, and Modbus-based telemetry, the XOS supports 24/7 autonomous operation in pump stations, reservoirs, or watershed monitoring kiosks.
What calibration standards and frequency are recommended?
Certified multi-element aqueous standards (e.g., NIST SRM 1643e) are used for initial calibration and quarterly verification. Drift correction is performed automatically using internal reference channels and blank subtraction routines.
Can the XOS be integrated into existing SCADA or PLC infrastructure?
Yes. Native RS-485 Modbus RTU protocol allows direct read/write access to all operational parameters, measurement values, status flags, and alarm states — fully compatible with Siemens, Rockwell, Schneider, and Honeywell control platforms.