Table 2.

Results from the linear regression models of absorbances of exudate samples (Abs Ex₂₆₀ or Abs Ex₂₅₄) plotted against the mg C L ⁻¹ measured with the liquid TOC analyser and calibration standards plotted against the known standard concentration (Std_known), with absorbance of exudate samples and standards measured at 254 (Abs Std₂₆₀) and 260 nm. (Abs Std₂₆₀)

	Abs Ex260 vs TOC	Abs Std260 vs Stdknown	Abs Ex254 vs TOC	Abs Sdt254 vs Stdknown
	Best-fit values
Slope	0.0062	0.0071	0.0077	0.0123
Y-intercept	0.0508	0.0484	0.0533	0.055
1/slope	161.4	141.1	130.1	80.95
	95% Confidence Intervals
Slope	0.0059 to 0.0064	0.0070 to 0.0071	0.0072 to 0.0082	0.0122 to 0.0125
Y-intercept	0.0485 to 0.0531	0.0477 to 0.0491	0.0489 to 0.0576	0.0531 to 0.0569
	Goodness of Fit
r2	0.9586	0.9999	0.9090	0.9997
Equation	Y = 0.0062*X + 0.0508	Y = 0.0071*X + 0.0484	Y = 0.0077*X + 0.0533	Y = 0.0123*X + 0.055
n	102*	11	102*	11

*Fe and Zn deficient exudate samples were excluded from the regression model