Decay curve

The decay curve is used to validate extraction processes in accordance with normative requirements. This action is necessary to develop and specify suitable reproducible, as well as component-specific extraction parameters for routine inspection.

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Your enquiry

What is a decay curve?

There are various inspection methods for checking the technical cleanliness of a component, specifically the agitation, ultrasonics, pressure-rinsing and rinsing method. However, these inspection methods are not all suitable to the same extent for all components and each component has specific characteristics due to its geometry. It is necessary to prepare a decay curve to determine whether a method is suitable for checking the technical cleanliness of a specific item.

Quality Analysis determines the decay curve for you

At Quality Analysis we offer you reliable, efficient decay measurements and cleanliness analyses to determine the best method to inspect the technical cleanliness of your component. We would be pleased to advise you in advance about the possible cleaning methods and component-specific characteristics to keep the effort and costs for you as low as possible. Thanks to our careful residual dirt analyses undertaken using the latest equipment, you receive detailed information about the granulometry of the particles and the gravimetry. You then have everything you need to identify and control contamination in your ongoing production in future.

You will find more information on our webpage covering particulate contamination.

Decay measurement to check the technical cleanliness of a component

How is a decay curve prepared?

One and the same component is sampled up to six times in succession to determine a decay curve. Important here: the conditions for the sampling action (initial parameters) such as pressure, quantity of solvent, exposure time, etc. must not be changed during the process.

After each of these 6 individual sampling actions, the detached particles are collected and conditioned in a filter membrane with a specified filter rating. There then follows a fully automatic microscopic analysis for the particle size class and quantity of metallic and non-metallic particles.

Evaluation of the decay curve

The quantity of particles must drop after each sampling action. If these results are depicted graphically, the eponymous decay curve is produced. However, when is the method applied to be considered validated?

After the sixth cleaning operation, the quantity of particles must be 10 percent or less of the total quantity of particles eluted (decay criterion). If so, the method applied and the underlying parameters can be considered validated for cleaning the component sampled. Conversely, if the residual contamination is higher, a different method or modified initial parameters must be selected and then the complete decay measurement repeated on a new test piece.

Your Contact

Selina Krieg


+49 7022 2796-633