The reason why was because I thought that the Arduino might be turned off before I got it to the computer, but if I have an external battery and run the program and store the values, then plug it into the computer and upload it, that could work. Thanks for the idea!
In that case then if the loop only reads the analog values from the sensor and stores them - no calculations or other process later in the loop -, how close to 25ms per store do you think that I could get using SRAM?