Advanced uses of smartphones are changing lifestyles, and may have a great impact in materials science in the near future. In this work, the use of these devices to develop fast, simple, and cheap methods to characterize magnetic nanoparticle suspensions is tested. A series of dilutions of a wide library of magnetic nanoparticles, composed of iron oxide materials in the range between 3 and 43 nm, with two different shapes and four different coatings is prepared. The colloid color is analyzed using the RGB (red, green, blue) color model. Ratios of these parameters are correlated with the suspension iron concentration and with the nanoparticles average size. A linear relationship between the color (in particular the G/R ratio) and both the colloid iron content and the particles size is found. The link between these parameters allows the development of two new methods to determine either the concentration or the particle size of magnetic nanoparticle suspensions just by acquiring images from suspensions of iron oxide magnetic nanoparticles with a smartphone.

中文翻译：

---

基于智能手机的比色法可量化铁浓度并从悬浮的磁性纳米粒子确定纳米粒子的尺寸

智能手机的高级使用正在改变生活方式，并且可能在不久的将来对材料科学产生巨大影响。在这项工作中，测试了使用这些设备开发出快速，简单和廉价的方法来表征磁性纳米颗粒悬浮液的能力。制备了一系列广泛的磁性纳米颗粒稀释液，这些磁性纳米颗粒由3到43 nm之间的氧化铁材料组成，具有两种不同的形状和四种不同的涂层。使用RGB（红色，绿色，蓝色）颜色模型分析胶体颜色。这些参数的比率与悬浮铁浓度和纳米颗粒的平均尺寸相关。发现颜色（特别是G / R比）与胶体铁含量和颗粒尺寸之间呈线性关系。