Overcoming inductively coupled plasma (ICP) washout is one of the main concerns scientists face when using these instruments to analyze samples due to the risk of contamination. The term ‘washout’ refers to removing a sample solution from the sample introduction system throughout the analysis process. Throughout this post, we will examine what ICP washout is and how it can be overcome to improve your laboratory analysis processes.
What is ICP?
Inductively coupled plasma (ICP) mass spectrometry (or ICP-MS), is a version of mass spectroscopy where an inductively coupled plasma is used to ionize a sample. This works because ICP is a high-temperature ionization source which offers high sensitivity and accurate analysis when used to detect elements at trace levels in biological samples. ICP-MS is used in various applications, including environmental monitoring, food testing, pharmaceutical analysis, etc.
What is ICP Washout?
ICP washout is the withdrawal of a sample solution from an instrument once it has been analyzed. If the previous sample is not entirely removed from the instrument before the new sample is introduced, this could cause contamination problems. Carryover contamination can create many problems for analysts, including incorrect test results and increased maintenance. It is, therefore, crucial that ICP washout problems are identified and addressed promptly.
Some of the main issues lie in the solution matrix, including components such as HNO3, HCI, HF and NH4OH and elements that may “stick” to the plastics used in your equipment. Other reasons why washout issues may occur include using a single-pass spray chamber, using the sub-optimal acids for rinsing protocols or not rinsing the equipment for long enough.
How do we Overcome ICP Washout?
There are several ways to overcome ICP washout. These include using a double-pass spray chamber instead of a single pass because this will allow for a quicker, more effective rinsing process. Frequently changing tubing or other instrument components and regular maintenance will also help to reduce the risk of contamination. Different solutions for ICP washout are outlined below and discussed in some of Inorganic Ventures’ webinars.
Monitoring Output
Suppose your instrument software package enables you to monitor real-time output. In that case, this is an effective way to measure rinse processes, including how long it takes and how successful the utilized rinse solutions are. When using different rinse solutions, you can compare the time it takes to complete a rinse cycle and whether it effectively removed the sample. From this data, you can make informed decisions about your rinse solutions.
Rinse Solutions
To ensure your washout process is as effective as possible, we recommend you use rinse solutions to suit your application. Standard rinse solutions include deionized water, HNO3, HCI, and even HF. However, these have limitations and must be used between a specific percentage. Additionally, you might want to consider speciality or customized rinse solutions to ensure you have the most appropriate choice. Inorganic Ventures will soon be launching a brand-new range of specialty rinses for common, persistent elements of concern such as boron, mercury, molybdenum, silicon, tungsten, and more. Refer to our product range in the coming months for more details.
Use Appropriate Materials
Ensuring the plastics used will not react with the samples. A typical problem occurs if PVC tubing is used for the peristaltic pump because many elements will stick to it and cause washout issues. This problem can be overcome by introducing a syringe drive or a switching valve system, preventing the sample from coming into contact with the PVC tube.
ICP Washout Solutions with Inorganic Ventures
Inorganic Ventures creates products to help overcome the issues related to ICP washout. We develop custom solutions to suit your applications, allowing you to specify the exact elements and concentration ranges required. Using custom solutions significantly reduces the risk of carryover contamination, thus allowing you to accurately and effectively analyze samples.
Our upcoming line of specialty rinse solutions includes a suite of custom products designed to resolve specific elements of concern. Contact our team of experts today for more information about our custom solutions.