Achieving 12-Hour Fragrance Longevity in a Water-Based Spray

Based on the information provided, achieving a fragrance spray that lasts 12 hours primarily depends on the nature of the fragrance oil itself, not just the fixatives or solvents used. While ingredients like Dipropylene Glycol (DPG) and the formulation base can help extend the scent duration, they typically provide a limited increase, perhaps from 30 minutes to around 60 minutes, rather than several hours.

Regarding your specific questions:

1. Amount of Dipropylene Glycol: There isn't a single fixed amount of Dipropylene Glycol to use with 1 part fragrance oil and 5 parts Flora Solve Clear. The optimal amount would depend on the specific fragrance oil and desired outcome. Dipropylene Glycol acts as a solvent and can help solubilize the fragrance oil and potentially contribute slightly to fixation, but its primary role here might be as part of the solvent system.
2. Effect of 5 parts Flora Solve Clear: Using a high proportion of Flora Solve Clear (5 parts) relative to the fragrance oil (1 part) might affect how the scent diffuses, especially if the fragrance oil contains many less volatile molecules. It could potentially make the scent less diffusive or seem weaker compared to a formulation with a different base (like alcohol, which aids evaporation).
3. Mixing Ratios for 12-hour Longevity: As mentioned, achieving 12 hours of longevity is highly dependent on the fragrance oil itself. No specific ratio of these four ingredients can guarantee this duration if the fragrance oil is composed mainly of fast-evaporating molecules. The formulation you described (fragrance oil, DPG, Flora Solve Clear, water) is a common approach for water-based fragrance sprays using a solubilizer, but its ability to achieve very long wear time is limited by the fragrance oil's inherent properties.
4. Mixing Method: A general method for mixing these ingredients would be to first mix the fragrance oil with the Dipropylene Glycol and Flora Solve Clear until the fragrance oil is fully solubilized. Then, gradually add the water while stirring until the mixture is clear and uniform. The specific ratios would need to be determined through experimentation based on the solubility of your particular fragrance oil and the desired scent strength and clarity.

To summarize, while your proposed ingredients are suitable for creating a water-based fragrance spray, the key to long-lasting scent is the selection of a fragrance oil designed for longevity. The formulation can support the fragrance, but it cannot fundamentally change the evaporation rate of the fragrance molecules themselves.