Unfortunately, since crude oil is comprised of thousands of complex components, it is hard to extract a generalized conclusion for the effect of salinities on the interface phenomenon. So, it seems applicable if any investigation performs regarding the interactions between each component of the crude oil especially resin (known as natural surfactants), and the salinities. In this way, this study is designed to find the effect of resin fraction (with a concentration of 1–8 % wt) extracted from a crude oil and salinities including NaCl, MgCl₂, KCl, and CaCl₂ in the range of low and high salinity (0–45,000 ppm). The measured IFT values revealed that as the resin is dissolved in the toluene, IFT reduces compared with the toluene solution contains no resin. Besides, the results reveal that as the resin concentration increases from 1 % wt to 4 % wt, the IFT reduction is more evident in the overall viewpoint although the IFT reduction is different for each salt and even reduces if the resin concentration increases to 8 %wt. So, it seems that there is a shifting value for the resin concentration (which is about 4 %wt) which leading to the lowest IFT values or the highest IFT reduction effect. Moreover, the inspections reveal that for the low resin concentration (1 %wt), CaCl₂ leading to the best IFT reduction behavior while for resin concentration of 4 %wt, KCl leading to the best IFT reduction behavior.

不幸的是，由于原油由数千种复杂成分组成，因此很难就盐度对界面现象的影响得出一个概括的结论。因此，如果对原油的每个成分，尤其是树脂（称为天然表面活性剂）和盐度之间的相互作用进行任何调查，这似乎是适用的。通过这种方式，本研究旨在发现从原油和盐分（包括 NaCl、MgCl ₂、KCl 和 CaCl _{2 ）中提取的树脂部分（浓度为 1-8 % wt）的影响}在低盐度和高盐度范围内 (0–45,000 ppm)。测量的 IFT 值表明，当树脂溶解在甲苯中时，与不含树脂的甲苯溶液相比，IFT 降低。此外，结果表明，随着树脂浓度从 1% wt 增加到 4% wt，IFT 降低在总体上更为明显，尽管每种盐的 IFT 降低不同，如果树脂浓度增加到 8%，IFT 降低甚至会降低重量。因此，似乎树脂浓度（约为 4 % wt）存在偏移值，导致 IFT 值最低或 IFT 降低效果最高。此外，检查表明，对于低树脂浓度（1 %wt），CaCl ₂ 导致最佳的 IFT 降低行为，而对于 4%wt 的树脂浓度，KCl 导致最佳的 IFT 降低行为。