Table 3.

Liver and serum levels of N-EtFOSE and its metabolites in female Sprague Dawley rats expressed as percentage of the total N-EtFOSE dose (%TD).^a

N-EtFOSE metabolitesb	%TD in Liver	%TD in Serumc
N-EtFOSE	-d	0.42 ± 0.20 (× 10-3) (n=5)
N-EtFOSAA	0.43 ± 0.13	0.38 ± 0.17
N-EtFOSA	n.d.	n.d.
FOSE	0.58 ± 0.35 (× 10-3)	0.07 ± 0.03 (× 10-3)
FOSA	0.29 ± 0.06	25.3 ± 6.1 (× 10-3)
PFOSe	6.23 ± 0.95	3.86 ± 0.86
Total	6.96 ± 0.92	3.69 ± 0.91

^aThe total dose of N-EtFOSE for each animal was calculated as

$${\text{TD}}_{N-\text{EtFOSE}}=\text{∑}_N(5\times b.w{.}_{\text{day}}),$$

where 5 is the daily N-EtFOSE dose of 5.0 mg/kg body weight, b.w._day is the body weight on each day of N-EtFOSE administration and n is the number of days of N-EtFOSE administration (n = 3 × 5 days).

^bAdjusted for the respective matrix spike recovery in serum (N-EtFOSE = 67%; N-EtFOSAA = 159%; N-EtFOSA = 82%; FOSE = 96%; FOSA = 132%) and in the liver (N-EtFOSE = 2.5±1%; N-EtFOSAA = 156±3%; N-EtFOSA = 19±2%; FOSE = 57±2%; FOSA = 98±3%) if not stated otherwise. See the experimental part and Table 2 for additional details.

^cCalculated assuming a serum volume of 4.86 mL/100 mg for female Sprague-Dawley rats (Probst et al., 2006).

^d %TD of N-EtFOSE in the liver is not reported because of the poor recovery rate (2.5±1%); also see Table 2.

^e Adjusted for the recovery of ¹³C₄-PFOS.