Which constituents are found in Zamboni fixative?

• A. Paraformaldehyde, Picric acid, sodium phosphate di- and monobasic
• B. Formaldehyde and potassium dichromate
• C. Acetic acid and picric acid
• D. Acetic acid only

Answer: (A)

Zamboni fixative combines an aldehyde source with a picric acid–based precipitating fixative and a buffering component. The aldehyde (in this form as paraformaldehyde) creates cross-links between proteins, stabilizing the structure of cells and tissues so that morphology and fine details are preserved. Picric acid rapidly penetrates and fixes cytoplasmic components and connective tissue, adding rigidity and helping with dye uptake for good staining contrast. The sodium phosphate di- and monobasic create a phosphate buffer that keeps the pH near an optimal level during fixation, preventing distortion or damage that can occur with pH shifts.

Together, these components give well-preserved morphology with reliable nuclear and cytoplasmic detail and compatible staining results, which is why this combination is characteristic of Zamboni fixative.