Yes, pH is a concentration, pKa is a dissociation constant, and pO2 is a partial pressure. These are (roughly speaking) ways to indicate how much of a key ingredient is in a mixture or how active it is.

When I go away for a long weekend and have unwashed dishes, I just soak them in extra-soapy water; arguably to do some pre-cleaning but mostly as a lame attempt at preventing life from taking hold and multiplying exponentially in the hot summer weather before I get back.

All soaps are not created equal

I want to ask in Biology SE about the level of soapiness necessary to prevent this from happening, but first I want to ask here if there is a way to quantify the soapiness of soapy water on some recognized or at least recognizable scale.

There is a wide range of soaps available in a household and when there's no dish detergent per se available and nobody is looking I've been known to use other products. A gram of laundry powder, window cleaner, bar soap, and dish detergent could potentially have very different levels of soapiness and therefore ability to strip living cells of their protective lipid membranes, either in bulk or just key, vulnerable constituents.

So I'd like to ask:

Question: For purposes of quantifying soapiness, is there a recognized, or at least recognizable parameter, something like p_soap or p_surfactancein like there's pH, pKa, and pO2 for other situations?

Yes, $\mathrm{pH}$ is a concentration, $\mathrm{p}K_\mathrm{a}$ is a dissociation constant, and $\mathrm{pO_2}$ is a partial pressure. These are (roughly speaking) ways to indicate how much of a key ingredient is in a mixture or how active it is.

When I go away for a long weekend and have unwashed dishes, I just soak them in extra-soapy water; arguably to do some pre-cleaning but mostly as a lame attempt at preventing life from taking hold and multiplying exponentially in the hot summer weather before I get back.

All soaps are not created equal

I want to ask in Biology SE about the level of soapiness necessary to prevent this from happening, but first I want to ask here if there is a way to quantify the soapiness of soapy water on some recognized or at least recognizable scale.

There is a wide range of soaps available in a household and when there's no dish detergent per se available and nobody is looking I've been known to use other products. A gram of laundry powder, window cleaner, bar soap, and dish detergent could potentially have very different levels of soapiness and therefore ability to strip living cells of their protective lipid membranes, either in bulk or just key, vulnerable constituents.

Question

For purposes of quantifying soapiness, is there a recognized, or at least recognizable parameter, something like p_soap or p_surfactancein like there's $\mathrm{pH},$ $\mathrm{p}K_\mathrm{a}$ and $\mathrm{pO_2}$ for other situations?

Yes pH is a concentration, pKa is a dissociation constant and pO2 is a partial pressure. These are (roughly speaking) ways to indicate how much of a key ingredient is in a mixture or how active it is.

When I go away for a long weekend and have unwashed dishes, I just soak them in extra-soapy water; arguably to do some pre-cleaning but mostly as a lame attempt at preventing life from taking hold and multiplying exponentially in the hot summer weather before I get back.

All soaps are not created equal

I want to ask in Biology SE about the level of soapiness necessary to prevent this from happening, but first I want to ask here if there is a way to quantify the soapiness of soapy water on some recognized or at least recognizable scale.

There are a wide range of soaps available in a household and when there's no dish detergent per se available and nobody is looking I've been known to use other products. A gram of laundry powder, window cleaner, bar soap and dish detergent could potentially have very different levels of soapiness and therefore ability to strip living cells of their protective lipid membranes, either in bulk or just key, vulnerable constituents.

So I'd like to ask:

Question: For purposes of quantifying soapiness, is there a recognized, or at least recognizable parameter, something like p_soap or p_surfactancein like there's pH, pKa and pO2 for other situations?

Yes, pH is a concentration, pKa is a dissociation constant, and pO2 is a partial pressure. These are (roughly speaking) ways to indicate how much of a key ingredient is in a mixture or how active it is.

When I go away for a long weekend and have unwashed dishes, I just soak them in extra-soapy water; arguably to do some pre-cleaning but mostly as a lame attempt at preventing life from taking hold and multiplying exponentially in the hot summer weather before I get back.

All soaps are not created equal

I want to ask in Biology SE about the level of soapiness necessary to prevent this from happening, but first I want to ask here if there is a way to quantify the soapiness of soapy water on some recognized or at least recognizable scale.

There is a wide range of soaps available in a household and when there's no dish detergent per se available and nobody is looking I've been known to use other products. A gram of laundry powder, window cleaner, bar soap, and dish detergent could potentially have very different levels of soapiness and therefore ability to strip living cells of their protective lipid membranes, either in bulk or just key, vulnerable constituents.

So I'd like to ask:

Question: For purposes of quantifying soapiness, is there a recognized, or at least recognizable parameter, something like p_soap or p_surfactancein like there's pH, pKa, and pO2 for other situations?