Typically, injection volumes are 10-1000 uL, however, both larger(e.g., 1-10 mL) and smalleg(e,gv uL) can be loaded by using special hardware such as an internal loop which is used for volumes as small as 20 nL Injection volumes for HPLC is relatively large compared to GC. Therefor, the use of external standards is more common than that of internal standards An important advantage of the loop valve design is that it is readily adapted to automatic operation. The automated sample injectors, or autosamplers, may be used to store and inject large numbers of samples.