Table 4:
Stability study of QC samples analysis.
Day
Standard curve
Recovery yield (%)
^{(1)}
Dynamic range of sulfur (mg)
Linear least squares regression equation
Correlation coefficient (
)
QC
_{coal}
^{ (2)}
QC
_{ECD}
^{ (3)}
1
0.032–0.105
Y = 1.627 × 10
^{−6}
X + 4.149 × 10
^{−3}
0.9994
101.10 ± 0.94
96.02 ± 2.33
2
0.033–0.103
Y = 1.629 × 10
^{−6}
X + 2.390 × 10
^{−3}
0.9994
99.82 ± 0.90
98.48 ± 1.96
3
0.031–0.105
Y = 1.609 × 10
^{−6}
X + 2.608 × 10
^{−3}
0.9997
101.72 ± 2.00
102.31 ± 1.63
^{(1)}
Data are expressed as average ± SD,
.
^{(2)}
QC
_{coal}
: 2.05 ± 0.05 mg of coal QC samples (S = 3.07%, w/w) were analyzed.
^{(3)}
QC
_{ECD}
: 7.52 ± 0.03 mg of ECD QC samples (ECD = 3.61%; S = 0.58%, w/w) were analyzed.