"certain quantities" is correct and usable in written English.
It can be used to refer to any set of measured or estimated amount of something. For example, "Certain quantities of sugar and oil must be added to the recipe in order to yield the desired flavor."
Of course it is possible to measure certain quantities.
When certain quantities or products have been bought, customers get either free merchandise or cash rebates.
Nutritionists, on the other hand, say it can interfere with medication and have harmful effects in certain quantities.
This means that the Wilson loop observables (WLOs) of the model considered can be obtained heuristically by integrating certain quantities against a functional measure of "Gaussian type".
Uhlenbeck is considered a technical wizard in the field of partial differential equations which are the equations that link certain quantities to their rates of change, and they appear basically everywhere in maths and also in physics.
The basic assumption is that this information refers to supply and demand and is expressed in the form of the expected values of certain quantities (such as inputs, resources, goods, production functions, utility functions and budgets).
But the aspirants must grow comfortable with a certain quantity of awkward pretense.
Polystyrene loaded with certain quantity of MWCNTs was uniaxially stretched to provide the nanotube alignment.
Such a formula is composed of a certain quantity of optimized functions and weights.
The first part stipulates that all states receive a certain quantity regardless of their population or risk status.
So, too, what is of a certain quantity extends itself over a certain space unless something prevents it.
