Field-deployable method for iron analysis using a simple preconcentration procedure and a 3D portable spectrophotometric system

In this paper, a field-deployable method for the spectrophotometric determination of iron after a simple preconcentration procedure in column is proposed. A 3D-printed portable system, housing a small spectrophotometer with a CCD detector and a LED as homemade light source is used for spectrophotometric detection. The entire system is powered through two USB outputs of a notebook. The Fe (III) preconcentration is based on a solid phase extraction with a column packed of Chelex-100 chelating resin. The Fe (III) eluted in the cuvette was reduced to Fe (II) and the iron concentration was determined using the o-phenanthroline method. Preconcentration factors between 9.7 and 98 were obtained. Under optimized conditions, linear calibration curves without and with preconcentration were constructed (R2 > 0.9992). Low LD (5 mu g L-1) and LQ (10 mu g L-1) were achieved, and good values for intra-day and inter-day precision were obtained (RSD < 2.9% and RSD < 9.6%, respectively). Recoveries of spiked iron in local tap water, sea water, well water, leachate and supernatant of anaerobic digester were ranged from 93 to 106%. The validation of method was also carried out by successfully analyzing a river water reference material SLRS-4.