Visual Quantification of Fe on Cotton Thread Using a Ruler

We described a simple method for detection of Fe on a thread-based analytical device. Fe reacts with 1,10-phenanthroline to form a colored band on a cotton thread; the length was measured to quantify the contents of Fe using a ruler. This method has the advantages of easy operation, low cost, easy fabrication, and reduced sample/reagent consumption. Furthermore, this method is free of any electronic equipment such as camera and digital scanner. These features make this method suitable as a laboratory experiment in universities and colleges. This laboratory experiment is designed as one of selected experiments of the Comprehensive Chemistry Experiment course for the students majoring in chemistry, for the sixth and seventh semester. The students enjoyed fabricating the thread-based analytical device and used it to detect the contents in unknown samples. This laboratory experiment could be completed within 3 h.