Final answer:
The highest quality cytology slide preparation is typically achieved through chemical fixation, with fixing in a 95% ethanol solution being a common and effective method for preserving delicate tissue specimens for staining and microscopic examination.
Step-by-step explanation:
To ensure the highest quality slide preparation in cytology, appropriate fixation of the specimen is crucial. Fixing a sample involves the process of attaching cells to a slide and preserving their structural integrity. Fixation can be achieved either by heating or by chemical means. For cytological preparations, which often include delicate tissue specimens, chemical fixation is usually preferred over heat fixation.
Chemical agents used for fixation include acetic acid, ethanol, methanol, formaldehyde (formalin), and glutaraldehyde. These chemicals denature proteins, halt biochemical reactions, and stabilize cellular structures, allowing for enhanced visualization under a microscope. Specifically, fixing in a 95% ethanol solution is a common practice that ensures the specimen is well-preserved for staining and subsequent microscopic examination.
Therefore, the correct answer to which step will ensure the highest quality slide preparation is fixing in 95% ethanol (option 3). This provides optimal preservation of the sample without causing the distortion that heat fixing might induce, especially on delicate tissue specimens.