V. Lo Turco

Influence of roasting and different brewing processes on the ochratoxin A content in coffee determined by high-performance liquid chromatography-fluorescence detection (HPLC-FLD)

A rapid and reliable procedure has been developed for the determination of ochratoxin A (OTA) in green and roasted coffee. The method consists of extraction of the sample with methanol–5% aqueous sodium hydrogen carbonate/1% PEG8000 (20:80), followed by immunoaffinity column (IAC) clean-up and, finally, high-performance liquid chromatography (HPLC) determination with fluorimetric detection. Mean recoveries for green and roasted coffee spiked at different levels ranging from 94 and 105% were obtained. The limit of determination (S/N = 3) was 0.032 ng g−1 and the precision (within-laboratory relative standard deviation) was 6%. The method described has been used to assess the influence of roasting and different brewing processes on OTA content in commercial lots of green and roasted coffee. The results provided evidence that roasting led to a significant drop on OTA levels (65–100%). Also, the way coffee is prepared affects the OTA content: brewing using a Moka Express (Italian coffee) led to a significant reduction of OTA concentration (50–75%) since hot water stays in contact with coffee for a short time. On the contrary, Turkish coffee-making (infusion for about 10 min) cause poor reduction in OTA.

Determination of trace elements in goat and ovine milk from Calabria (Italy) by ICP-AES.

There are many sources of contamination to which milk could be exposed: grazing animals can ingest contaminants present in nature, such as lead in soil, or that have been deposited on grass, resulting from industrial emissions. Another possible route of contamination is represented by feed for animals, which may contain heavy and essential metals. The potential of high-resolution inductively coupled plasma spectrometry was evaluated to quantify reliably various toxic and essential elements (Fe, Zn, Pb, Cr, Ni, Cu, As, Se, Cd) in 47 samples of goat and ovine milk from various farms in Calabria (southern Italy). The results showed that concentrations of cadmium were below the limit of detection. Lead levels were below the maximum limits as set by the EC in almost all samples tested. The highest values were those of Zn followed by Fe, Cu and Se.

Determination of copper, zinc, selenium, lead and cadmium in potatoes (Solanum tuberosum L.) using potentiometric stripping methods

Potentiometric stripping analysis was used to determine simultaneously the content of zinc(II), cadmium(II), lead(II) and copper(II) in potatoes, whereas the concentration of selenium was determined by cathodic stripping potentiometric analysis. Metal cations were extracted from potatoes by hydrogen peroxide/hydrochloric acid treatments. The relative standard deviation of the methods ranged from 2.3 to 4.1% and the detection limits were lower than 2.5 μg kg−1. The results obtained with the proposed methods were compared with those obtained with graphite furnace atomic absorption spectroscopy, a common method for determining metals. The results of the two methods agreed to within 6.1%. Twelve samples of yellow flesh potatoes from different cultivars were analysed. Of all the metals determined, Cu and Zn were the most abundant with concentrations between 0.5 and 4.6 mg kg−1. Selenium was only found in three samples in very low amounts (<0.1 mg kg−1), whilst Pb and Cd concentrations were in the range 0.01 − 0.27 mg kg−1.

Classification of the geographical origin of Italian donkey's milk based on differences in inorganic anions

The content of chlorides, nitrites, nitrates, phosphates and sulphates was used to classify 45 donkeys milk samples collected from different Italian regions. A method employing ion exchange chromatography with conductivity detector and chemical suppression was used. The quantitative results indicated phosphates (569.4–1304.4 mg kg−1) and chlorides (545.9–1757.9 mg kg−1) as being the most abundant anions, followed by sulphates (109.5–200.7 mg kg−1). The concentrations of nitrites and nitrates were found to be lower at 5.6 and 5.5 mg kg−1 respectively. The data set was subdivided into three groups according to the region of origin of milk, and was statistically evaluated by analysis of variance (ANOVA). Concentrations of chlorides and nitrites showed a significant difference among farms (p < 0.001). In a first discriminant analysis procedure, functions based on linear combinations of the log e -transformed element concentrations of anions were generated to classify donkeys milk samples from different regions. In an alternative approach, a three-step discriminant analysis procedure to classify a milk sample was tested. The results obtained led to a correct classification of donkeys milk samples based on their anions content with 91–98% of the samples being correctly classified. The procedure proved to be very simple, so it could be used as an evaluation method for the traceability of donkeys milk, thus defending this unique product against fraud or commercial disputes.

Levels of Cd (II), Mn (II), Pb (II), Cu (II), and Zn (II) in Common Buzzard (Buteo buteo) from Sicily (Italy) by Derivative Stripping Potentiometry

The purpose of this study was to determine the concentrations of heavy metals (Cd, Pb, Cu, Mn, and Zn) in different organs (liver, kidney, muscle, lung, skin, and feathers) of buzzards (Buteo buteo), utilized as a “biological indicator” for environmental contamination, from different areas of Sicily and to investigate the relationships between birds sex, age, and weight and metal levels in these samples. All samples of common buzzards were collected at the “Recovery Center of Wild Fauna” of Palermo, through the Zooprophilactic Institute. Potentiometric stripping analysis (PSA) was used to determine the content of Cd(II), Cu(II), Mn(II), Pb(II), and Zn(II) in bird tissues. For toxic metals, the highest levels of Pb were in liver and those of Cd in lung; Zn levels were higher than Cu and Mn in all tissues analyzed. The concentrations in liver, lung, kidney, and muscle could be considered as an indicative of chronic exposure to metals while the presence of metals in skin could be consequential to storing and elimination processes. The found concentrations of metals in the studied matrices required a highly sensitive method for their determination and a simple sample preparation procedure, and the proposed method was well suited for this purpose.

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

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 cows milk. There are no significant differences between ovine and goats 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.