The collagen triple helix structure is not found in -
Cytoplasm
Golgi apparatus
Lumen of endoplasmic reticulum
Intracellular vesicles
Triple helix formation occurs in endoplasmic reticulum at procollagen level.
Triple helix of procollagen is packed into secretory intracellular vesicles in the Golgi-apparatus.
These vesicles then secrete the procollagen into extracellular space where it is converted to tropocollagen (collagen monomer).
Tropocollagens aggregate into collagen fibrils which intern become extensively cross-linked to form 'collagen fibers'.