EPA Method 335.2 Instrumentation Guide

EPA Method 335.2 is a colorimetric procedure developed to determine cyanide concentrations in drinking water, surface water, and wastewater. The method involves two essential steps: manual reflux distillation and spectrophotometric detection of a red-colored complex at 578 nm. This dual-stage process requires high-precision equipment to ensure regulatory compliance. Laboratories must select UV-Vis spectrophotometers that support this detection wavelength and deliver reproducible measurements. Choosing the right instruments directly impacts the accuracy, sensitivity, and consistency of cyanide testing under Method 335.2.

A photo of AGILENT UV-VIS Spectrophotometer System for EPA Method 335.2 that links to a catalog of UV-Vis Spectrophotometer equipment.

Method 335.2 begins with distillation, which isolates cyanide as hydrogen cyanide (HCN) and absorbs it into a sodium hydroxide solution. Following this step, a red complex forms after adding chloramine-T and pyridine-barbituric acid reagents. Laboratories then measure absorbance using a UV-Vis spectrophotometer calibrated to 578 nm. Therefore, any instrument selected must offer precise wavelength control, strong signal stability, and compatibility with cuvette-based sample handling. The following UV-Vis systems from leading manufacturers meet these requirements and align with EPA protocols.

Please click here to learn more about Method 335.2

Agilent Cary 60 UV-Vis Spectrophotometer for EPA Method 335.2

The Agilent Cary 60 UV-Vis Spectrophotometer delivers rapid, accurate readings with strong optical stability, making it a trusted tool for Method 335.2. It uses a xenon flash lamp and fiber-optic sampling, which minimizes heat exposure and supports fast throughput. Its broad wavelength range includes 578 nm, enabling reliable detection of cyanide complexes. The system accommodates low-volume samples and supports durable field or laboratory use. With its responsive optics and long-term performance, the Cary 60 remains ideal for regulatory compliance workflows.

This system integrates seamlessly into existing analytical setups following manual distillation. Although it does not include reflux components, it offers consistent detection across multiple samples. Analysts benefit from the fast startup, user-friendly interface, and stable performance under routine operations. The Cary 60 also supports advanced software features for method storage and QA/QC tracking. As a result, labs using this system experience reduced measurement errors and streamlined data reporting. It remains a top-performing choice for accurate cyanide analysis by Method 335.2.

Thermo Scientific GENESYS 30 Visible Spectrophotometer for EPA Method 335.2

The Thermo Scientific GENESYS 30 Visible Spectrophotometer provides reliable fixed-wavelength analysis at 578 nm, as required by EPA Method 335.2. It features a compact footprint, intuitive touchscreen interface, and streamlined workflows ideal for small and mid-sized laboratories. While it does not include automated distillation or complex software, it excels at core colorimetric absorbance measurements. This simplicity makes it well-suited for routine water testing environments that need cost-effective, method-compliant instrumentation without sacrificing data quality or detection sensitivity.

After distillation, laboratories use the GENESYS 30 to quantify the red chromophore formed during the colorimetric reaction. Its precise optics and stable baseline ensure repeatable absorbance results for each sample. This instrument is especially useful for labs with moderate throughput and limited technical resources. Its affordability, low maintenance, and consistent performance make it an excellent fit for compliance monitoring under EPA Method 335.2. The GENESYS 30 also integrates with common sample handling tools and delivers strong value for environmental labs.

Hach DR6000 UV-Vis Spectrophotometer for EPA Method 335.2

The Hach DR6000 UV-Vis Spectrophotometer combines laboratory-grade performance with user-friendly features tailored for regulatory compliance. It supports detection at 578 nm and includes pre-programmed protocols for EPA methods, including cyanide testing. With its integrated QA tools, the DR6000 simplifies method validation, calibration, and results tracking. Designed for high-throughput water labs, this instrument accelerates sample turnaround while maintaining excellent measurement precision. Moreover, it works seamlessly with Hach’s cuvettes and reagent systems, reducing setup complexity and improving workflow standardization.

Following reflux distillation, labs use the DR6000 to measure cyanide through absorbance of the red dye complex. Its automated reporting, built-in quality checks, and intuitive controls make it ideal for municipal or industrial labs managing large sample volumes. In addition, the DR6000’s rugged design supports long-term operation in demanding environments. It provides excellent accuracy and regulatory traceability across a range of water matrices. For labs requiring reliable, high-volume analysis under Method 335.2, this instrument is a proven and scalable solution.

Shimadzu UV-1280 UV-Vis Spectrophotometer for EPA Method 335.2

The Shimadzu UV-1280 UV-Vis Spectrophotometer features dual-beam optics and scanning capabilities that enhance precision for trace-level absorbance detection. Its broad wavelength range includes 578 nm, making it fully compatible with Method 335.2. This instrument supports both fixed-wavelength and programmable method operations, giving labs flexibility to standardize cyanide workflows. Built-in validation features help labs maintain calibration accuracy over time. Its durable build and consistent performance make the UV-1280 a strong fit for routine testing in compliance-focused environments.

After distillation, laboratories load samples into cuvettes for direct absorbance measurement. The UV-1280 produces repeatable results across multiple runs, improving confidence in reported values. Its simple interface and customizable menus support a wide range of EPA and non-EPA methods. This instrument also enables method storage, auto-zeroing, and batch QA tracking. Laboratories benefit from its affordability, analytical consistency, and data reliability. As a result, the Shimadzu UV-1280 offers a high-value solution for accurate cyanide analysis under EPA Method 335.2.

Choosing the Right UV-Vis Spectrophotometer for EPA Method 335.2

  • For high-throughput regulatory labs: The Hach DR6000 offers EPA-aligned protocols, fast sample turnaround, and integrated QA/QC tools to support efficient cyanide testing.
  • For advanced flexibility: The Shimadzu UV-1280 provides dual-beam accuracy, programmable workflows, and robust scanning capabilities for consistent post-distillation colorimetric analysis.
  • For budget-conscious workflows: The Thermo Scientific GENESYS 30 delivers dependable fixed-wavelength detection and user-friendly operation, ideal for routine compliance testing.
  • For fast, fiber-optic performance: The Agilent Cary 60 UV-Vis combines high-speed absorbance readings with durable optics, making it ideal for labs seeking precision and throughput.

EPA Method 335.2 requires accurate absorbance measurement at 578 nm following manual cyanide distillation. Each of the spectrophotometers listed above supports this requirement with high-performance optics, stability, and method-compliant functionality. Whether you’re upgrading your lab or launching new testing programs, these systems offer reliable and efficient solutions. Contact us today to explore certified UV-Vis instruments optimized for EPA Method 335.2 and ready to support your water compliance goals with confidence.