EPA Method 350.1 Instrumentation Guide

EPA Method 350.1 is a widely used colorimetric procedure for determining ammonia nitrogen concentrations in drinking water, wastewater, and other aqueous samples. This method employs the phenate reaction to form indophenol blue, which is then measured colorimetrically to quantify ammonia levels. It is frequently applied in Clean Water Act compliance monitoring and routine nutrient analysis. With automation capabilities and robust sample handling, Method 350.1 allows laboratories to process large volumes of samples with precision and consistency.

A photo of a refurbished THERMO SCIENTIFIC VIS Spectrophotometer system for EPA METHOD 350.1 that links to a catalog of VIS Spectrophotometer equipment.

To ensure full compliance with EPA 350.1, laboratories must utilize instrumentation designed for semi-automated colorimetric analysis. Continuous flow analyzers and compatible UV-Vis spectrophotometers play a central role in automating the phenate method, improving detection sensitivity and minimizing analyst error. Below, we explore proven analytical systems from leading brands that meet the method’s stringent requirements, providing laboratories with reliable and scalable solutions for ammonia nitrogen testing.

Please click here to learn more about Method 350.1.

Thermo Scientific GENESYS 30 VIS Spectrophotometer for EPA Method 350.1

The Thermo Scientific GENESYS 30 VIS is a compact and user-friendly visible spectrophotometer that supports ammonia nitrogen analysis using the phenate method described in EPA Method 350.1. With a wavelength range of 325 to 1100 nm, the system offers precise colorimetric measurements and reliable performance for drinking water, wastewater, and environmental samples. Its advanced optics and intuitive interface make it ideal for laboratories seeking a cost-effective solution for compliant ammonia testing.

While EPA 350.1 typically uses continuous flow analyzers for high-throughput testing, the GENESYS 30 offers a viable alternative for laboratories with moderate sample volumes or manual phenate workflows. It supports DPD and indophenol blue detection and ensures accurate, reproducible readings with minimal maintenance. Its small footprint and robust construction make it suitable for both bench-top and field applications in ammonia nitrogen monitoring.

SEAL AQ400 Discrete Analyzer for EPA Method 350.1

The SEAL AQ400 is a fully automated discrete analyzer designed for colorimetric ammonia nitrogen testing under EPA Method 350.1. Using the phenate method, it automates reagent dosing, reaction timing, and absorbance measurement for precise quantification of ammonia in drinking water and wastewater. Its temperature-controlled reaction wells ensure consistent color development, while built-in quality control protocols support compliance with Clean Water Act requirements.

Unlike continuous flow systems, the AQ400 runs each sample as an individual test, minimizing cross-contamination and reducing reagent waste. This platform supports high-throughput laboratories with up to 200 tests per hour and flexible rack layouts for simultaneous multi-parameter analysis. With its intuitive software interface and compliance-ready performance, the AQ400 is an excellent choice for labs needing fast, accurate ammonia detection aligned with EPA 350.1 standards.

Lachat QuikChem 8500 Series 2 FIA System for EPA Method 350.1

The Lachat QuikChem 8500 Series 2, developed by Hach, is a flow injection analyzer that offers precise and reliable ammonia nitrogen analysis in accordance with EPA Method 350.1. This modular system uses segmented flow technology with tightly controlled reaction times and colorimetric detection, making it ideal for analyzing low-level ammonia in a wide range of water matrices. The phenate method is fully automated with high sensitivity and reproducibility.

Designed for environmental labs requiring high throughput and low carryover, the QuikChem 8500 supports up to 120 samples per hour with automated calibration and QC sample handling. Its ChemStation software provides customizable methods, integrated diagnostics, and regulatory data reporting. With proven accuracy and consistent performance, the QuikChem 8500 is widely trusted for EPA-compliant nutrient analysis in drinking water, surface water, and wastewater applications.

Skalar San++ Continuous Flow Analyzer for EPA Method 350.1

The Skalar San++ Continuous Flow Analyzer is engineered for fully automated wet chemistry workflows, including ammonia nitrogen determination by the phenate method under EPA Method 350.1. This instrument uses a segmented flow design with in-line reagent mixing, temperature-controlled reaction coils, and a photometric detector to produce high-precision results across diverse water sample types. It supports both manual and auto-dilution for extended calibration range.

The San++ is tailored for environmental and municipal laboratories seeking robust automation, minimal hands-on time, and regulatory traceability. It can process hundreds of samples per day with real-time monitoring, automated drift correction, and LIMS-compatible data output. As one of the most versatile and widely adopted CFA platforms, the San++ ensures method compliance, reliability, and scalability for laboratories tasked with ammonia nitrogen monitoring under the Clean Water Act.

OI Analytical Flow Solution 3700 for EPA Method 350.1

The Flow Solution 3700 by OI Analytical (Xylem) is a purpose-built continuous flow analyzer optimized for regulatory ammonia testing using the phenate method defined in EPA Method 350.1. This system automates all stages of sample analysis—from reagent mixing and color development to absorbance detection—delivering reproducible results for ammonia concentrations in both treated and untreated water samples.

Featuring modular components and high sensitivity detectors, the Flow Solution 3700 accommodates inline sample distillation, matrix matching, and flexible channel configurations for simultaneous multi-parameter testing. With up to 150 sample analyses per hour, it’s an ideal choice for government, industrial, and contract labs that require dependable throughput, method compliance, and long-term operational stability. The system’s clarity in performance and EPA alignment make it a strong fit for ammonia nitrogen monitoring in environmental compliance programs.

Choosing the Right Instrumentation for EPA Method 350.1

  • For automated high-throughput testing: The SEAL AQ400, Skalar San++, and Lachat QuikChem 8500 offer scalable automation and built-in compliance features.
  • For performance with modular flexibility: The OI Analytical Flow Solution 3700 delivers precision and EPA-aligned workflow customization.
  • For small labs or budget-conscious setups: The Thermo Scientific GENESYS 30 provides an accessible, compliant solution for routine ammonia monitoring.

EPA Method 350.1 remains a standard for ammonia nitrogen determination, requiring precise colorimetric detection and dependable instrumentation. Whether you’re operating a large environmental lab or a small municipal facility, selecting the right analyzer is critical to meeting regulatory standards and achieving consistent, high-quality data. We offer certified refurbished analyzers and spectrophotometers that align with EPA 350.1 performance requirements—contact us today to find the right solution for your ammonia nitrogen testing needs.