TABLE 1.

Performance of the analytical method

Retention time, limit of detection, and linear range (R² ≥ 0.99) for ESI-MS detection in SRM mode, and UV detection at 265 nm are shown.

Compound	Retention Time	LC-ESI(−)-MS/MS		UV
		LOD	LOQ Linear Range	LOD	LOQ Linear Range
	min	fmol	nM	fmol	nM
DCC	4.36 ± 0.03	3	1–1000	300	100–10,000
TCC	5.10 ± 0.04	3	1–1000	300	100–10,000
2′-OH-TCC	6.81 ± 0.07	3	1–1000	300	100–10,000
6′-OH-TCC	7.45 ± 0.05	3	1–1000	300	100–10,000
3′-OH-TCC	4.61 ± 0.02	3	1–1000	300	100–10,000
2′-SO3-O-TCC	3.46 ± 0.02	3	1–1000	300	100–10,000
N-Gluc-TCC	1.97 ± 0.01	n.d.	n.d.	n.d.	n.d.
N′-Gluc-TCC	2.07 ± 0.02	n.d.	n.d.	n.d.	n.d.
2′-O-gluc-TCC	2.50 ± 0.02	10	3–1000	300	100–10,000
6′-O-gluc-TCC	2.51 ± 0.02	n.d.	n.d.	n.d.	n.d.
3′-O-gluc-TCC	2.26 ± 0.02	n.d.	n.d.	n.d.	n.d.

LOQ, limit of quantitation; n.d., not determined because no reference compound was available.