Comparative spectrophotometric determination of the total iron content in various white and red Greek wines

Iron content in a satisfactory number of bottled and non-bottled white, rosé and red Greek wines has been determined in this work. The wines analyzed were from various regions of Greece. Iron content was determined using two modified spectrophotometric methods. The classical method of Fe(III)-thiocyanate complex formation has been properly modified to work in a sulfuric acid medium, and in the presence of potassium persulfate (K2S2O8) as an oxidant. The second method, involved the use of the compound 2-(5-nitro-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)-amino]-phenol disodium salt (Nitro-PAPS, C17H19O6N5SNa2), known for its highly sensitive reaction with Fe(II). The experimental results of the two methods were found to be in good agreement with those obtained using the Atomic Absorption Spectroscopy (AAS) method. The proposed methods are rapid, accurate, simple, relatively inexpensive and can be used for all types of wine (white, rosé and red). Therefore, they may be used for the iron assay in routine wine analyses, as an alternative to the AAS method. The values of iron content determined in the Greek white, rosé and red wines were in the range 1.00 to 10.00 mg/l.