Table 2. Regression Equations and Correlation Coefficients of the Three Tracers.

tracer	the regression equation	linear range (ppb)	R2	LOD (ppb)	LOQ (ppb)	RSD (%)
2,3,4,5-tetrafluorobe-nzoic acid	Y = −556105 + 156351 × X	1–1000	0.9961	0.033	0.17	0.64
2,6-difluorobenzoic acid	Y = −259278 + 18782.2 × X	1–1000	0.9998	0.024	0.12	1.51
3,4-difluorobenzoic acid	Y = 1.78006e + 006 + 78125.8 × X	1–1000	0.9942	0.032	0.1	0.8