Additional Resources

cyanide guide

Cyanide Analysis Guide

Simultaneous Analysis of Available and Total Cyanide by Gas Diffusion Amperometric Methods USEPA OIA-1677 and ASTM D 7511-12

Cyanide Analysis of Wastewater Samples from FCC and Hydrocracking Operations

USEPA Method OIA-1677: A Novel Approach to Cyanide Analysis

Cyanide Measurement and Analysis


What is Cyanide?

what is cyanide
Outside of a rare earth element mining facility, likely mining for gold or silver where cyanide is used in leaching the desired elements from the ore.

A cyanide is a compound that has a C≡N functional group, or a carbon atom triple-bonded to a nitrogen atom. Like many other ions, cyanide reacts rapidly and takes on many forms in the ambient environment.

Cyanides occur as a result of both natural and industrial processes, and they must be monitored very closely because exposure to cyanide can be potentially deadly.

cyanides analysis in industrial processes
Industrial facilities use cyanide for many different applications.
inorganic cyanide toxic

Inorganic cyanides exist as anions and are extremely poisonous. Ex: sodium cyanide, potassium cyanide, and hydrogen cyanide gas.

organic cyanide nitriles

Organic cyanides are usually called nitriles, and are not nearly as toxic. Ex: cyanoacrylates, acetonitrile, and acetone cyanohydrin.

cyanide byproducts tailing pond
Although necessary for storing and diluting hazardous byproducts of the mining process, water also spreads tailings across a vast area of our planet.

tailings pond cyanide
A tailings pond designed to keep hazardous materials away from potable water.

A significant portion of artificial cyanide in soil and water originates from industrial processes. The remainder is a result of metal mining (gold, precious metals), iron, steel, and chemical manufacturing, and publicly owned treatment works (POTW). Cyanide is also released from tobacco smoke, sewage, fires, and is naturally released by certain species of plants, bacterium, and fungi.

sources of cyanide emission

cyanide emission sources natural artificial

Why do we monitor cyanide?

Cyanide analysis involves the examination and quantification of cyanide compounds in various environmental samples, such as water, soil, and air. Using advanced, regulated analytical techniques, scientists and associated professionals can accurately assess the present levels of cyanide and evaluate the environmental risk.

Along with other chemical analyses, cyanide analysis has a critical role in safeguarding both human and environmental health. By monitoring cyanide levels, we can identify potential sources of contamination, implement appropriate preventive measures, and assess the effectiveness of mitigation strategies. Such analysis enables us to:

Evaluate Environmental Impact

Cyanide contamination can lead to severe ecological consequences, particularly in aquatic ecosystems. Through rigorous analysis, we can accurately assess the extent of cyanide pollution, identify vulnerable areas, and implement targeted conservation measures to protect fragile ecosystems.

Ensure Compliance with Regulatory Standards

Regulatory bodies have established maximum contaminant levels (MCLs) for cyanide in drinking water, setting thresholds to protect public health. Accurate analysis is essential to ensure compliance with these standards and mitigate the risks associated with cyanide exposure.

Cyanide contamination must be monitored very closely, as compounds such as sodium cyanide and hydrogen cyanide gas can wreak havoc on the environment.

cyanide contamination analysis water monitoring

sodium cyanide port tianjin explosion
Port of Tianjin, China after the series of explosions of a chemical storage station in 2015. The stored chemicals included large quantities of sodium cyanide, calcium carbide, ammonium nitrate, and potassium nitrate.

Regulations and Methodologies

Due to the toxic nature of cyanide compounds and their potential impact on ecosystems and human health, analysis plays a pivotal role in environmental monitoring and safety compliance. Accurate and reliable analysis methods are essential for assessing cyanide levels, ensuring regulatory compliance, and implementing effective mitigation techniques.

The regulations and methodologies established by organizations such as the Environmental Protection Agency (EPA), the American Society for Testing and Materials (ASTM), and the International Organization for Standardization (ISO) enable standard measurement, regardless of region or application.

Below, we will explore these regulatory frameworks to give us a comprehensive understanding of the measures in place to monitor and control cyanide contamination:


The sudden awareness of our environmental impact in the United States in the 1960's led to the establishment of the Environmental Protection Agency (EPA), and the implementation and adherence to a great swathe of new environmental legislation. EPA has approved and set methods for pollutants with many acts, including CWA, CAA, RCRA, as well as many others.

cyanide analysis epa drinking water limit

These are the methods EPA has approved for cyanide analysis:

USEPA 9010-9020
USEPA method OIA-1677
USEPA method 335.4


ASTM has defined several standardized methodologies for cyanide analysis at an international level. These methods ensure consistency and accuracy across laboratories and facilitate data comparison and compliance. These are the ASTM standard methods related to cyanide analysis:

  • ASTM D 7511: Standard Test Method for Total Cyanide by Segmented Flow Injection Analysis, In-Line Ultraviolet Digestion and Amperometric Detection
  • ASTM D 7237: Standard Test Method for Free Cyanide and Aquatic Free Cyanide with Flow Injection Analysis (FIA) Utilizing Gas Diffusion Separation and Amperometric Detection
  • ASTM D 6888: Standard Test Method for Available Cyanides with Ligand Displacement and Flow Injection Analysis (FIA) Utilizing Gas Diffusion Separation and Amperometric Detection
  • ASTM D 7365: Standard Practice for Sampling, Preservation and Mitigating Interferences in Water Samples for Analysis of Cyanide
  • ASTM D 7572: Standard Guide for Recovery of Aqueous Cyanides by Extraction from Mine Rock and Soil
  • ASTM D 2036: Standard Test Methods for Cyanides in Water
  • ASTM D 7728: Methods for International Cyanide Management Code


ISO has developed globally recognized standards for cyanide analysis, harmonizing methodologies and ensuring consistency in data interpretation. Notable ISO standards for cyanide analysis include:

  • ISO 16264: Determination of cyanide in soil - Method using flow injection analysis (FIA) and gas-diffusion separation.
  • ISO 14403: Determination of total cyanide and free cyanide by continuous flow analysis

Cyanide Speciation

Cyanide speciation refers to th echaracterization of different forms of cyanide present in a sample. Identification and quantification of cyanide species was a necessary step towards the development of analytical methods, as multiple forms of cyanide exist simultaneously in the environment.

total wad free cyanide

forms and species of cyanide

cyanide forms water solid gas

Total cyanide represents the sum of all cyanide species present in a sample, including free cyanide, WAD cyanide, and strong metal-cyanide complexes. Total cyanide methods provide a comprehensive understanding of the sample's overall cyanide content, making this parameter useful for regulatory compliance and risk assessment.

Weak acid dissociable (WAD) cyanide refers to cyanide species that can be released under weak acid conditions of pH of 3 to 6. This fraction includes both free cyanide and weakly bound metal-cyanide complexes.

Free cyanide refers to the chemically unbound and highly toxic form of cyanide. It is capable of binding to metals, inhibiting essential enzymatic processes, and posing a significant risk to human health and the environment. Monitoring and controlling free cyanide levels are essential in industries such as mining, metallurgy, and electroplating.

how cyanides move in the environment

cyanides produced gas water free cyanide in environment

how tailings discharge release cyanide environment

tailings discharge in water soil

The carbon to nitrogen (C/N) ratio is used to evaluate the organic matter decomposition process. In the context of cyanide speciation, the C/N ratio can be important in understanding the potential for the degradation or detoxification of cyanide compounds. Microorganisms can utilize carbon and nitrogen sources for metabolic processes, which can affect the fate of cyanide compounds in natural or engineered systems.


Cyanide is highly toxic to living organisms, including humans. The toxicity of cyanide is primarily attributed to its ability to interfere with cellular respiration by inhibiting the activity of enzymes involved in the electron transport chain. Cyanide poisoning can lead to severe health effects, and therefore, monitoring cyanide levels and understanding its speciation are crucial for ensuring workplace safety and environmental protection.

cyanide illegal mining washing minerals
Sudan, 2023, where activists have demanded for cessation of all illegal mining operations washing minerals using cyanide. People, livestock, and birds have died due to the lack of enforced regulation.


cyanide monitoring gold mining

cyanide cyanidation in gold mining


Cyanide is extensively used in gold and silver extraction processes (leaching, more specifically cyanidation), and analysis is performed to ensure both safety of workers and the environment from contamination. Accurate monitoring of cyanide concentrations in various process streams, tailings, and environmental samples is essential for compliance with regulatory requirements. Implementing and following proper cyanide analysis methods lets companies safeguard the well-being of their employees and minimize the impact on surrounding ecosystems.

cyanide concentration monitoring wastewater electroplating


Cyanide is utilized in the electroplating process to dissolve and deposit a metal onto another surface, a method accomplished by passing an electric current through a solution (containing cyanide). Cyanide-based solutions are commonly used in the electroplating industry for clearing metal doposition that accmulates on surfaces. Cyanide concentrations are monitored in both electroplating baths and facility wastewater. With this data companies can mitigate the risks associated with cyanide exposure and comply with environmental regulations.

cyanide monitoring wastewater iron steel production

Iron and Steel Production

Cyanides are used in pickling and cleaning operations in iron and steel production. Cyanide analysis in this industry is conducted to monitor cyanide concentrations in process solutions and wastewater. Implementing appropriate cyanide analysis methods helps in assessing and controlling cyanide concentration in facility water, preventing the release of cyanide-laden effluents that would have detrimental effects on ecosystems and public health.

chemical production process inorganic cyanide

Plastics & Specialty Chemicals

Certain specialty chemical production processes involve the use of inorganic cyanides. With cyanide (or any other dangerous substance), monitoring and analyzing levels enable chemical companies to implement appropriate measures to prevent the release of harmful substances into the environment. Cyanide analysis is essential in this industry to validate cleaning procedures and ensure proper handling, storage, and disposal of cyanide-containing compounds.

pharmaceutical manufacturing inorganic cyanides


In Pharmaceutical manufacturing, inorganic cyanides may be used in specific synthesis or purification processes. Routine analysis for hazardous chemicals is crucial to ensure product quality and safety. Monitoring of cyanide concentrations during pharmaceutical production and wastewater treatment helps mitigate potential health risks and prevent environmental contamination. Standard cyanide analysis methods enable pharmaceutical companies to uphold the highest standards of safety and regulatory compliance for their products.

cyanide analysis hydraulic fracturing groundwater

Hydraulic Fracturing

In hydraulic fracturing (fracking) operations, small amounts of inorganic cyanides may be present in fracking fluids. Cyanide analysis is performed to ensure compliance with environmental regulations and protect groundwater resources. Employing reliable cyanide analysis allows for the mitigation of some of the harmful side effects of fracking. Businesses can demonstrate their commitment to safety, regulatory compliance, and environmental stewardship by prioritizing cyanide analysis in hydraulic fracturing.

Monitoring and Process Control

In industries where inorganic cyanides are used, such as mining, electroplating, iron and steel production, specialty chemical production, pharmaceuticals, and fracking, effective monitoring and process control instrumentation are vital for ensuring safety, regulatory compliance, and environmental protection. This section delves into various techniques and instruments employed in cyanide analysis, including titration, continuous flow analysis (CFA), online monitoring, and their associated chemical methods and parameters.

Colorimetric Detection: Beyond Titration

Titration is a widely employed technique in cyanide analysis, providing accurate determination of cyanide concentrations in diverse samples. The titration method relies on the chemical reaction between cyanide ions and a titrant, often silver nitrate (AgNO3), resulting in the formation of a precipitate of silver cyanide (AgCN). The endpoint of the titration is typically detected using a silver-specific indicator, such as potassium chromate (K2CrO4), which forms a red precipitate when all cyanide ions have reacted with the silver.

Colorimetric detection methods, such as ASTM D7511 and ASTM D6888, offer detailed guidelines for the determination of cyanide in various matrices, including water samples and process solutions. These methods ensure accurate and reliable results by controlling critical parameters such as pH, temperature, and reaction time. The careful selection of appropriate indicators and titrants, as specified by the methods, ensures optimal performance and precision in cyanide analysis.

Continuous Flow Analysis (CFA): High Throughput Analysis

automated chemistry analyzer cyanide analysis

Continuous flow analysis, also known as segmented flow analysis, is highly automated technique used for cyanide analysis. This method enables high sample throughput and precise results with minimal manual intervention. CFA systems comprise pumps, valves, and detectors that continuously process samples in a controlled manner.

Methods like ASTM D2036, D7511, D6888, and D7237 are commonly employed for cyanide analysis using CFA. These methods vary, but often involve a combination of distillation and subsequent analysis using colorimetric or amperometric detection.

In ASTM D6888 and OIA-1677, the distillation step is replaced by gas diffusion separation, which allows for more efficient separation of cyanide from the sample matrix followed by amperometric detection. This ensures accurate and efficient analysis of cyanide concentrations, even in the most complex of matrices.

Segmented flow analysis (SFA) and flow injection analysis (FIA) are the most frequently used CFA methods for cyanide analysis. SFA and FIA offer precise control of sample injection volumes and reagent flow rates, enhancing the accuracy and reproducibility of cyanide analysis. These methods also allow for the integration of additional detection techniques such as colorimetric detection or amperometric detection, providing flexibility in analysis and improving sensitivity.

Online Monitoring: Immediacy and Simplicity

Online monitoring systems provide real-time data on cyanide concentrations, delivering immediate feedback for process control and decision-making. These systems utilize sensors or probes specifically designed for cyanide detection. The sensors employ various principles, including electrochemical, optical, or ion-selective methods, to measure cyanide levels in the sample.

Online monitoring systems are particularly valuable in industries where continuous monitoring is critical, such as mining and fracking. By continuously monitoring cyanide concentrations in process streams, wastewater, or ambient air, potential issues can be identified promptly, allowing for immediate corrective actions to prevent environmental contamination or health hazards.

Parameters such as pH and temperature play crucial roles in cyanide analysis, as they can significantly affect the stability and reactivity of various cyanide species. Therefore, monitoring and controlling these parameters are essential for accurate and reliable cyanide analysis.

online cyanide analyzer


The importance of cyanide analysis cannot be overstated. Analysis in industries around the world allows for the detection and quantification of cyanide levels, enabling effective control measures to prevent its release into the environment. Regulation helps companies abide by strict discharge limits, and required analysis helps businesses work for the betterment of the world and humanity.