Inorganic anions in goat and ovine milk from Calabria (Italy) by suppressed ion chromatography

Abstract

Forty-seven samples of milk taken from goat and ovine farms in Calabria (southern Italy) between April and May 2010 were analysed. Analyses were carried out by ion chromatography (ICS 1000; Dionex). For method validation, RSDs (%) on retention times and on peak area were determined by considering a mixture of standard anions at the concentration level of 0.1–30 mg l⁻¹ for chloride, bromide, nitrite, nitrate, sulfate and phosphate. The higher RSDs were 1.4% and 2.2% for retention times and 2.4% and 3.7% for areas for intra- and inter-day repeatability, respectively. Good linearity was observed in each concentration range, with linear correlation coefficients (R ²) better than 0.987. The LODs and LOQs were calculated experimentally as signal-to-noise ratios of 3 and 10, respectively. Analysis of the results obtained indicated that phosphates were the most abundant anion (1409–3050 mg l⁻¹) followed by chloride (679–2568 mg l⁻¹) and sulfates (25–341 mg l⁻¹). Nitrates were found to be lower at 146 mg l⁻¹ (the maximum value observed). The values of anions found in this work are in agreement with those reported in the literature for cow's milk. There are no significant differences between ovine and goat's milk samples. The method used for this analysis of anions combines rapidity with high precision, accuracy and sensitivity; therefore, it is suitable for routine analysis. Moreover, one of the most obvious advantages of this technique is that multiple elements can be determined in one sample with no serial dilutions and the complete analysis can be performed by using only one instrument.

Keywords:

• goat and ovine milk
• inorganic anions
• ion chromatography