Table 1. Parameters of the HPLC–MS/MS detection of Thd dimeric photoproducts in the positive (ESP+) and negative (ESP–) electrospray ionization modes.
Product | ||||||
---|---|---|---|---|---|---|
<>c,s | <>t,s | <>c,a | <>t,a | (6–4) | Spore | |
Retention time (min) | 16.8 | 17.1/17.6 | 18.9/19.2 | 23.4 | 23.0/25.4 | 25.6/27.6 |
ESP+ | 253 | 253 | 127 | 127 | 235 | 253 |
ESP– | 350 | 350 | 125 | 241 | n.d.a | 279 |
Parent ions were set at m/z = 485 and 483, respectively. Detection in the multiple reaction monitoring mode involved the daughter ions listed. Retention times are provided for the single or the (+) and (–) diastereoisomers of each photoproduct. <>c,a, <>c,s, <>t,s and <>t,a, cis,anti, cis,syn, trans,syn and trans,anti cyclobutane dimers; (6–4), (6–4) photoproduct; spore, spore photoproduct.
aThymidine (6–4) photoproducts are ionized in very low yield in the negative mode and cannot be quantified under these conditions.