Producing Phosphorus-32: A Radioactive Isotope with Scientific Applications

Introduction to Phosphorus-32

Phosphorus-32 (32P) is a radioactive isotope of the element phosphorus with a half-life of approximately 14.3 days. This isotope is widely used in various scientific and medical applications, including biological research, medical diagnostics and targeted cancer therapy. Understanding the production of 32P is critical to ensuring a reliable and consistent supply of this important radioisotope.

In this comprehensive article, we will explore the different methods used to produce phosphorus-32, highlighting the key considerations and challenges involved in the process.

Nuclear reactor-based production

The most common method of producing 32P is through nuclear reactor-based techniques. In this approach, a stable isotope of sulphur, sulphur-32 (32S), is subjected to neutron bombardment in a nuclear reactor. The neutrons interact with the 32S nuclei, causing them to undergo a nuclear reaction that transforms them into 32P.
The nuclear reaction involved in this process is known as the (n,p) reaction, where the neutron (n) interacts with the sulphur-32 nucleus, resulting in the production of a proton (p) and the formation of the desired phosphorus-32 isotope. This method is highly efficient and can yield large quantities of 32P, making it a widely used approach in the scientific and medical communities.

One of the key advantages of nuclear reactor-based production is the ability to precisely control and monitor the production process, ensuring a consistent and reliable supply of 32P. In addition, the use of existing nuclear infrastructure, such as research reactors, can help streamline the production process and reduce costs.

Particle accelerator based production

An alternative method of producing 32P involves the use of particle accelerators. In this approach, a stable isotope of sulphur, sulphur-31 (31S), is bombarded with protons, resulting in the formation of 32P through a different nuclear reaction.
The nuclear reaction in this case is known as the (p,n) reaction, where the proton (p) interacts with the sulphur-31 nucleus, resulting in the emission of a neutron (n) and the production of the desired phosphorus-32 isotope. Particle accelerator-based production can be a useful alternative when access to nuclear reactors is limited or when specific application requirements necessitate a different production method.

An advantage of particle accelerator-based production is the ability to tailor the energy of the incident protons to optimise the yield and purity of the 32P produced. This flexibility can be particularly beneficial for specialised applications where high purity 32P is required.

Radiochemical purification

Regardless of the production method, the harvested 32P often requires further radiochemical purification to remove any unwanted by-products or impurities. This purification process typically involves a series of chemical separation techniques, such as ion exchange chromatography or solvent extraction, to isolate the 32P from the other radioactive and non-radioactive species present in the starting product.
The radiochemical purification step is essential to ensure the high quality and safety of the 32P used in various applications. It helps to minimise the presence of unwanted radioactive impurities that could adversely affect the intended use of the isotope.

Applications of Phosphorus-32

Phosphorus-32 has a wide range of applications in science and medicine. In biological research, 32P is commonly used as a radioactive tracer to study various cellular and molecular processes such as DNA replication, protein synthesis and enzyme activity.

In the medical field, 32P has found use in targeted cancer therapy, where it is administered to patients as a radiopharmaceutical. The beta particles emitted by 32P can selectively damage and destroy cancer cells, making it a valuable tool in the fight against certain cancers such as polycythemia vera and certain types of leukaemia.

In addition, 32P has applications in nuclear medicine, where it can be used to diagnose and monitor various medical conditions, such as bone metabolism and liver function.


Phosphorus-32 is an important radioisotope with many scientific and medical applications. Both nuclear reactor-based and particle accelerator-based methods are used to produce 32P, each with its own advantages and considerations. Ensuring the high quality and purity of the produced 32P through radiochemical purification is essential for its effective and safe use.

As technology and research continue to develop, the production and application of phosphorus-32 is likely to continue to play an important role in advancing scientific understanding and improving medical treatments. By understanding the various production methods and the importance of 32P, researchers and healthcare providers can use this valuable radioisotope to further their respective fields.


Here are 5-7 questions and answers about how phosphorus 32 is made:

How is phosphorus 32 made?

Phosphorus 32 (32P) is a radioactive isotope of phosphorus that is commonly produced in a nuclear reactor. It is made by irradiating a sample of stable phosphorus 31 (31P) with neutrons, which causes some of the 31P atoms to undergo a nuclear reaction and transform into 32P atoms. The 32P isotope is then chemically separated from the original sample.

What is the nuclear reaction that produces phosphorus 32?

The nuclear reaction that produces 32P is a neutron capture reaction. Specifically, the stable 31P isotope captures a neutron to become 32P, according to the nuclear equation: 31P + n → 32P + γ, where n represents a neutron and γ represents a gamma ray that is emitted in the reaction.

How is the phosphorus 32 isolated and purified?

After the 31P sample is irradiated in a nuclear reactor, the 32P isotope must be chemically separated and purified. This is typically done by dissolving the irradiated sample in an acid solution and then using ion exchange chromatography or other separation techniques to isolate the 32P from the other elements present.

What are some common uses of phosphorus 32?

Phosphorus 32 has several important applications, particularly in the field of biology and medicine. It is commonly used as a radioactive tracer to study metabolic processes in living organisms. 32P is also used in cancer treatments, where it can be administered to patients to help destroy cancerous cells.

What are the safety considerations when handling phosphorus 32?

Phosphorus 32 is a high-energy beta emitter, which means it can pose a significant health risk if not handled properly. Appropriate safety precautions, such as the use of shielding, containment, and personal protective equipment, must be taken when working with 32P to minimize the risk of exposure and contamination.