Identification of blood meal in fertilizers

Abstract

A simple and useful analytical method is proposed for the characterization of blood meal fertilizer, a quality organic fertilizer commonly used in agriculture. Despite the agronomical and commercial importance of this organic fertilizer, Italian law does not indicate an analytical method for its identification in organic matrices. This situation is very unsatisfactory because unscrupulous producers could declare the presence of a quality organic fertilizer, such as blood meal, instead of a poorer fertilizer. In this work the heme group of the hemoglobin contained in blood meal was characterized spectrophotometrically and a calibration curve prepared using different concentrations of hemoglobin was used to determine the hemoglobin content in six blood meal samples. The method was successfully applied for the qualitative identification of hemoglobin in mixtures of organic and/or organic fertilizers with small amounts (3–10%) of blood meal.