'predetermined time interval' is correct and usable in written English.
You can use it to refer to an amount of time that has been specified in advance, and that is not subject to change. For example, "We have a predetermined time interval of one hour for conducting the experiment."
The withdrawal of 2 ml of the external medium from the system was done at predetermined time interval, replaced by an equal volume of fresh medium, and filtered through a 0.45-μm membrane.
At predetermined time interval, samples (3 ml) were withdrawn, replaced with same volume of fresh media, filtered, and assayed for drug content at 231 nm against blank using UV visible spectrophotometer.
At the end of predetermined time interval, the content was filtered and the supernatant was analyzed for residual concentration of phenol spectrophotometrically (APHA et al. 1995) using UV visible spectrophotometer (Systronics, Vis double beem Spectro 1203).
The first report of learning used electrical stimuli to train a neural response to occur within a predetermined time interval [45].
After a predetermined time interval, the tea bag was taken out and dried in the air for 15 min.
C-ring type specimens coupled or not coupled with GECM are inspected for cracks at certain (predetermined) time intervals.
At predetermined time intervals, 1.0 mL of release buffer was removed for analysis, and 1.0 mL of fresh PBS (with 0.5% SDS) was added to continue the incubation.
At predetermined time intervals, 2 mL of solution was withdrawn, and the amount of 5-FU released from the ZIF-8/5-FU@FA-CHI-5-FAM was examined at 265 nm by recording the UV absorbance of the solution.
Variations of DEPFETs can be tuned to specific requirements as to be sensitive only in predetermined time intervals, to measure signal charge with sub-electron precision, dead-time-free readout and with signal compression.
At predetermined time intervals of 5 min, 1 mL of release media was withdrawn and passed through 0.45-µm filter.
Cell morphologies were observed under a phase contrast microscope (Nikon Eclipse TS100, Tokyo, Japan) at predetermined time intervals.
