Florida Sen. Marco Rubio, left, currently holds a comfortable lead against both of his potential Democratic opponents. (Bill Clark/CQ Roll Call file photo)

A new Quinnipiac University poll shows three Republican incumbent senators leading their would-be Democratic opponents.

The poll released Thursday shows Ohio Sen. Rob Portman leading former Gov. Ted Strickland by 7 percentage points, a jump from the previous poll which had seen the two in a statistical tie.

Portman appears to have a significant fundraising advantage over Strickland, with $13 million in cash on hand. Strickland has lagged in fundraising in the past but has yet to release his second quarter numbers.

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In Pennsylvania, GOP Sen. Patrick J. Toomey is beating Katie McGinty , former chief of staff to Gov. Tom Wolf, by 10 points.

Toomey has consistently led in polls against McGinty as well her Democratic primary challenger, former Rep. Joe Sestak when he was polled by Quinnipiac.

Similarly, in Florida, Sen. Marco Rubio has consolidated his lead over both of his potential Democratic opponents , Reps. Patrick Murphy and Alan Grayson. Republicans pushed hard for Rubio to run for re-election since he was widely seen as their best option to hold the seat.

Murphy, who has received the endorsement of President Barack Obama and Vice President Joseph R. Biden Jr., has been criticized after local news reports showed discrepancies in his resume. Rubio leads Murphy by 13 points and he leads Grayson, who is largely opposed by the Democratic establishment, by 12 points.

The poll also shows President Barack Obama's approval ratings underwater in all three states.

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