50 / 258
10
H
ostetler
:
J
ournal of
AOAC I
nternational
V
ol
.
100, N
o
.
3, 2017
Table 2. Residuals and error of back-calculated concentrations for all-
trans
-lutein standard curves
All-
trans
-lutein
concn, μg/100 mL
Experiment 1
Experiment 2
Experiment 3
Residual
Error, %
Residual
Error, %
Residual
Error, %
235.9
0.000368916
0.01
–0.000497233
–0.02
–6.16301E-05
0.00
125.8
–0.003210486
0.24
–0.00122698
0.09
0.00221285
–0.16
78.6
0.00379152
–0.44
0.003308385
–0.38
–0.004609309
0.54
31.5
0.000817163
–0.24
0.000644834
–0.18
0.003230669
–0.93
3.93
–0.001767113
3.78
–0.002229005
4.65
–0.00077258
1.65
Table 3. Residuals and error of back-calculated concentrations for all-
trans
-β-carotene standard curves
All-
trans
-β-carotene
concn, μg/100 mL
Experiment 1
Experiment 2
Experiment 3
Residual
Error, %
Residual
Error, %
Residual
Error, %
227.4
0.00125077
0.05
0.002290766
0.09
–0.001591824
–0.06
121.3
–0.002520458
–0.18
–0.003680882
–0.27
0.00318571
0.23
75.8
–0.000366823
–0.04
–0.00193471
–0.23
–0.000338007
–0.04
30.3
0.001615483
0.47
0.002244522
0.65
0.000226108
0.06
3.79
2.10278E-05
0.04
0.001080305
2.33
–0.001481986
–2.97
Table 4. Calculated concentrations (μg/100 g) for all-
trans
-lutein and all-
trans
-β-carotene in the control formula (milk-based
infant formula) using the original standard curve and using zero as the
y
-intercept
Analyte
Experiment 1
Experiment 2
Experiment 3
Zero-intercept Orig. curve
a
Diff ., %
b
Zero-intercept Orig. curve Diff., % Zero-intercept Orig. curve Diff., %
Lutein
4.5
4.4
–1.9
4.4
4.3
–2.9
4.4
4.4
–1.4
β-Carotene
13.1
13.0
–0.9
13.0
13.0
–0.3
13.0
12.9
–0.5
a
Orig. = Original.
b
Diff. = Difference.
Table 5. Calculated concentrations (μg/100 g) for all-
trans
-lutein and all-
trans
-β-carotene in a FOS/GOS-fortified infant
formula using the original standard curve and using zero as the
y
-intercept
a
Analyte
Experiment 1
Experiment 2
Experiment 3
Zero-intercept Orig. curve
b
Diff., %
c
Zero-intercept Orig. curve Diff., % Zero-intercept Orig. curve Diff., %
Lutein
0.86
0.83
–3.5
0.86
0.78
–8.8
0.95
0.87
–8.3
β-Carotene
3.3
3.3
–1.6
3.3
3.3
–2.3
3.6
3.5
–2.6
a
FOS/GOS = Fructooligosaccharide/galactooligosaccharide.
b
Orig. = Original.
c
Diff. = Difference.
Table 6. LOD and LOQ for lutein in spiked SRM 1849a
Sample
Measured
concn,
μg/100 g S/N
Extrapolated
LOD, μg/100 g
Extrapolated LOQ,
μg/100 g
1
1.40
68.6
0.06
0.20
2
1.46
70.4
0.06
0.21
3
1.43
37.0
0.12
0.39
Average
0.08
0.27
Table 7. LOD and LOQ for β-carotene in spiked SRM 1849a
Sample
Measured concn,
μg/100 g
S/N
Extrapolated
LOD, μg/100 g
Extrapolated
LOQ, μg/100 g
1
1.62
61.6
0.08
0.26
2
1.70
61.2
0.08
0.28
3
1.66
61.0
0.08
0.27
Average
0.08
0.27
50