SPSFAM Heavy Metals ERP Book

K ubachka et al .: J ournal of AOAC I nternational V ol . 100, N o . 4, 2017  1083

Table 3. Average, SD, minimum, and maximum spike recoveries in RTD apple, grape, and pear juices and apple juice concentrate

Nominal spike level, µg/kg

Average spike recovery, %

SD spike recovery, %

Minimum spike recovery, %

Maximum spike recovery, %

Analyte

Matrix

No. of Labs No. of replicates

AJ1 AJ1 AJ1 GJ1 GJ1 GJ1 PJ1 PJ1 PJ1 AJ1 AJ1 AJ1 GJ1 GJ1 GJ1 PJ1 PJ1 PJ1 AJ1 AJ1 AJ1 GJ1 GJ1 GJ1 PJ1 PJ1 PJ1

8 8 8 8 8 8 8 8 8 8 8 8 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7

16 16 16 16 16 16 16 16 16 16 16 16 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14

5 As(III) + 5 As(V) 25 As(III) + 25 As(V) 50 As(III) + 50 As(V) 5 As(III) + 5 As(V) 25 As(III) + 25 As(V) 50 As(III) + 50 As(V) 5 As(III) + 5 As(V) 25 As(III) + 25 As(V) 50 As(III) + 50 As(V) 35 As(III) + 35 As(V) 100 As(III) + 100 As(V) 200 As(III) + 200 As(V)

104 104 102 101

11

88 91 83 86 81 89 83 88 88 89 85 91 86 92 89 90 82 89 91 96 92 94 82 82 82 94 89 89 82 84 80 89 90 89 80 87

125 117 119 115 106 106 109 106 108 119 119 120 119 115 115 110 107 104 120 117 117 110 105 106 114 110 109 118 105 110 130 116 108 113 109 105

7 9 8 6 4 8 6 6 9 6 6 6 6 5 8 6 7 5 7 7 9 5 6 8 8 7 8 5 7 9 6 8

97 98 97 98 97

iAs a

AJC1 AJC1 AJC1

105 103 104 102 102 101

10

5 DMA 25 DMA 50 DMA 5 DMA 25 DMA 50 DMA 5 DMA 25 DMA 50 DMA 35 DMA 100 DMA 200 DMA 5 MMA 25 MMA 50 MMA 5 MMA 25 MMA 50 MMA 5 MMA 25 MMA 50 MMA 35 MMA 100 MMA 200 MMA

10

99 97 98

DMA

101 103 102 100

AJC1 AJC1 AJC1

97 98

101 101 100 105

96 98 98

MMA

15

101 100 100

AJC1 AJC1 AJC1

97 97

a  Measured as As(III) + As(V).

Thenominalspikeconcentrationsintheapplejuiceconcentrate were higher than those for RTD juices because of the additional sample dilution that is required before analysis. The nominal spike concentrations were 35, 100, and 200 µg/kg for As(III), As(V), DMA, and MMA. Overall, fortification recoveries in apple juice concentrate were very good, with averages ±1 SD of 104 ± 9, 98 ± 7, and 98 ± 7% for iAs ( n = 48), DMA ( n = 42), and MMA ( n = 42), respectively. None of the recoveries were outside the 80–120% acceptable range. The results in Table 3 for the RTD juices and the apple juice concentrate do not appear

to show any significant differences in recoveries based on juice type and/or fortification level. These fortification recovery results for apple, grape, and pear RTD juices and apple juice concentrate demonstrate acceptable accuracy and precision of the method over the range of concentrations of interest and do not indicate any significant matrix interferences, including signal enhancement for iAs, DMA, and MMA, in these sample types. Sample fortifications provided a good proxy for t R assessment of standard versus spiked sample. In general, As(V) and MMA