Research Article

Evaluation of Copper and Manganese Concentrations in Commercial Fruit Juices and Nectars Consumed in Brazil by GF AAS

Table 3

Results obtained in the evaluation of the calibration strategy using samples of different flavors.

Calibration strategy/sampleType of sample/flavorCuaMna

Analytical curveWaterY = (0.0090 ± 0.0002) x + (0.0048 ± 0.0055), r2 = 0.999Y = (0.0347±) x + (0.0026 ± 0.0044), r2 = 0.998
Analyte addition curve/S2Nectar/orangeY = (0.0094x ± 0.0003) x + (0.1347 ± 0.0039), r2 = 0.999, SR = 1.04, t value = 2.495Y = (0.0316±) x + (0.3432 ± 0.0184), r2 = 0.991, SR = 0.91, t value = 2.784
Analyte addition curve/S6Nectar/mangoY = (0.0106x ± 0.0009) x + (0.0830 ± 0.0074), r2 = 0.999, SR = 1.18, t value = 4.277Y = (0.0332±) x + (0.4046 ± 0.0128), r2 = 0.997, SR = 0.93, t value = 1.653
Analyte addition curve/S9Nectar/passion fruitY = (0.0099x ± 0.0005) x + (0.0428 ± 0.0022), r2 = 0.999, SR = 1.10, t value = 3.869Y = (0.0310±) x + (0.2016 ± 0.0181), r2 = 0.998, SR = 0.89, t value = 2.543
Analyte addition curve/S12Nectar/peachY = (0.0100x ± 0.0008)x + (0.113 ± 0.0085), r2 = 0.999, SR = 1.11, t value = 3.214Y = (0.0345±) x + (0.2512 ± 0.0175), r2 = 0.995, SR = 0.99, t value = 0.149
Analyte addition curve/S16Nectar/grapeY = (0.0099x ± 0.0008) x + (0.0897 ± 0.0076), r2 = 0.998, SR = 1.10, t value = 2.665Y = (0.0293±) x + (0.2878 ± 0.0297), r2 = 0.996, SR = 0.84, t value = 3.521
Analyte addition curve/S20Juice/orangeY = (0.0087x ± 0.0004) x + (0.1168 ± 0.0055), r2 = 0.999, SR = 0.96, t value = 1.466Y = (0.0284±) x + (0.2353 ± 0.0281), r2 = 0.999, SR = 0.82, t value = 3.816
Analyte addition curve/S22Juice/grapeY = (0.0144x ± 0.0005) x + (0.2910 ± 0.0096), r2 = 0.993, SR = 1.60, t value = 24.051Y = (0.0628±) x + (0.1035 ± 0.0062), r2 = 0.993, SR = 1.81, t value = 15.924

aSR represents the slope ratios and were calculated as Sadc/Sac, where Sac = the sensitivity (slope) of the analytical curve and Sadc = sensitivity (slope) of the analyte addition curve. Y represents the integrated absorbance (s) and x is the concentration of the analyte (µg L−1). tvalue was compared to tcritical = 4.30 (degrees of freedom = 2 at 95% confidence level).