I have never heard lipophilic, non-polar, and hydrophobic used as synonyms. They aren't really are they?
A. Put a liter of liquid chemical X and a liter of water in a two-liter jar, shake it, and let it stand for a while. When you come back, if there is only one layer, you say chemical X is "miscible." If you have two layers of about one liter each, you say chemical X is "hydrophobic." If you have two layers, but the layer with X is less than one liter, you say X is "soluble in water." You can describe this exactly, as 5.0 grams of X per 100 mL of water, implying that if you try to mix more than 5.0 grams with 100 mL of water the second layer will form, if you mix less than 5.0 there will not be a second layer. Often qualitative terms such as "poorly soluble" are used. Most hydrophobic substances are non-polar and most non-polar substances are hydrophobic, but the word "hydrophobic" is qualitative and hydrophobicity is relative. Both methanol CH3OH and octanol C8H17OH have the same polar character (how about "amount of polarity" hmm.) in the OH or alcohol group. Octanol has a lot more non-polar character in the rest of the molecule than methanol, by an amount of 1:8 (roughly). So octanol is hydrophobic and non-polar (as a whole), methanol is both miscible with water and non-polar substances, like hydrocarbons. Likewise the word "lipophilic" is qualitative. The analysis of Kow is a method of measuring lipophilicity. But in general most non-polar substances tend to be hydrophobic, and have a high Kow and thus are lipophilic. No they are not synonyms.
Interference.
For many analytical chemical methods, certain other chemical interfere with the analysis. Some will appear to the analytical instruments to be the same as the chemical of interest, and therefore increase the results reported for the contaminant of interest. Others types of interferences will mask the chemical of interest.