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(∑y) (∑𝑥 2 ) – (∑x) (∑xy) 𝑎= n (∑𝑥 2 ) − (∑𝑥 2 ) 𝑎=

(1,87) (227500) – (1050) (419,8) 6 (227500) − (10502 )

𝑎=

425.425 – 440.790 (1.365.000) − (1.102.500)

𝑎=

−15365 262.500

a = -0,059 𝑏=

n(∑xy) − (∑x) (∑y) n (∑𝑥 2 ) − (∑𝑥 2 )

𝑏=

6(419,8) − (1050) (1,87) 6 (227500) − (1.102.500)

𝑏=

2.518,8 − 1963,5 1365009 − 1102500

𝑏=

555,3 262500

b = 0,00212 Persamaan regresi y = a + bx = -0,059 + 0,00212x Menentukan konsentrasi pada sampel a) Sampel 1  y = a + bx 0,400 = -0,059 + 0,00212x 0,00212x = 0,400 + 0,059 0,00212x = 0,459 x = 212,51 ppm  y = a + bx 0,397 = -0,059 + 0,00212x 0,00212x = 0,397 + 0,059 0,00212x = 0,456

x = 215,09 ppm x=

216,5 +215,09 2

= 215,8 ppm FP (faktor pengenceran) = 1 mL menjadi 10 Ml FP =

v labu v sampel

FP =

10 mL 1 mL

FP = 10 x = 215,8 ppm x FP = 215,8 ppm x 10 = 2158 ppm b) Sampel ikan  0,152 = -0,059 + 0,00212x 0,00212x = 0,152 + 0,059 0,00212x = 0,211 x = 99,53 ppm  0,151 = -0059 + 0,00212x 0,00212x = 0,151 + 0,059 0,00212x = 0,21 x = 99,06 ppm x=

99,53+99,06 2

= 99,295ppm x = 99,295 ppm x FP = 99.295 x 10 = 992,95 ppm