Table 5: Robustness study in the analysis of ECD.
 Parameter Standard curve of coal(1) QCcoal (2) Linear least squares regression equation Correlation coefficient ( ) Sulfur weight (%) Recovery yield (%)(3) Dosing time (sec) 90 Y = 1.544 × 10−6X + 3.394 × 10−3 0.9992 3.14 ± 0.06 102.36 ± 2.58 120 Y = 1.615 × 10−6X + 4.747 × 10−3 0.9993 3.13 ± 0.07 101.91 ± 2.30 150 Y = 1.604 × 10−6X + 7.508 × 10−4 0.9999 3.05 ± 0.10 99.17 ± 2.84 Temperature of combustion tube (°C) 1120 Y = 1.605 × 10−6X + 8.215 × 10−4 0.9997 3.13 ± 0.06 102.01 ± 1.85 1150 Y = 1.615 × 10−6X + 4.747 × 10−3 0.9993 3.13 ± 0.07 101.91 ± 2.30 1180 Y = 1.586 × 10−6X + 1.126 × 10−3 0.9985 3.03 ± 0.03 98.68 ± 1.14 Temperature of reduction tube (°C) 850 Y = 1.621 × 10−6X + 9.226 × 10−5 0.9997 3.12 ± 0.06 102.01 ± 1.75 900 Y = 1.615 × 10−6X + 4.747 × 10−3 0.9993 3.13 ± 0.07 101.91 ± 2.30 950 Y = 1.649 × 10−6X − 1.288 × 10−3 0.9996 3.00 ± 0.02 97.97 ± 0.87
(1)Standard curves were constructed by the coal concentration range of 1.01 to 3.49 mg.
(2)Data are expressed as average ± SD, .
(3)Recovery yield (%) = Sulfur(mg)exp/Sulfur(mg)nominal  × 100%.