Donald Trump remains ahead of Hillary Clinton among white voters in Ohio, Pennsylvania, and Florida. | Getty Swing-state polls: Trump slipping in Florida, Ohio

Donald Trump slipped farther behind Hillary Clinton in Florida, lost his narrow advantage in Ohio and remained locked in a dead heat in Pennsylvania, according to the results of the latest Quinnipiac University poll gauging voter attitudes in the those three swing states out Tuesday.

Clinton leads Trump by eight points in Florida, 47 percent to 39 percent, up seven points overall from May when she was clinging to a 43 percent-to-42 percent advantage. Trump's advantage among Florida men dropped 9 points over the last month, from a 13-point lead to just four points, 45 percent to 41 percent in June. Among women in Florida, Clinton's advantage grew by 5 points, from 48 percent to 35 percent last month to 52 percent to 34 percent in the post recent survey. White voters support Trump over Clinton 51 percent to 36 percent, while non-white voters backed Clinton 72 percent to 8 percent.

In Ohio, Clinton and Trump are knotted at 40 percent each, after the presumptive Republican nominee led by 4 points (43 percent to 39 percent) last month. Trump's 17-point lead among men in May is virtually the same this time, at 15 points. Among white voters, Trump leads 46 percent to 32 percent, but among non-whites, Clinton leads by 70 points, 78 percent to 8 percent.

The race changed little from the last month in Pennsylvania, with Clinton up 42 percent to 41 percent, comparable to the same results from May (43 percent to 42 percent in favor of Clinton). While Clinton leads 50 percent to 34 percent among women, Trump leads 50 percent to 33 percent among men. Among white voters, Trump leads 47 percent to 38 percent, while Clinton leads among non-whites 66 percent to 15 percent.

On a series of character and moral traits, majorities or pluralities of voters in all three states said Clinton is better prepared to be president, has higher moral standards and is more intelligent. Meanwhile, Trump led Clinton in all three states on which candidate is seen as more honest and trustworthy and is a stronger leader. Voters in both Ohio and Pennsylvania said Trump is more inspiring, while Florida voters favored Clinton slightly in that respect.

In terms of who voters think would be better at creating jobs, Trump is seen as the superior candidate in all three states, while Clinton is seen as a better candidate to handle immigration in Florida, Ohio and Pennsylvania. And while voters in all three states preferred Trump to Clinton with respect to who would be most effective in fighting the Islamic State, Clinton is seen as better to handle an international crisis.

With third-party candidates in the mix, Clinton leads Trump 42 percent to 36 percent in Florida, while Libertarian nominee Gary Johnson drew 7 percent and 3 percent went for Green Party candidate Jill Stein. In Ohio, Clinton earned 38 percent, Trump grabbed 36 percent, Johnson received 8 percent and Stein got 3 percent. In Pennsylvania, Clinton opened up a slight lead of 39 percent to 36 percent, with 9 percent for Johnson and 4 percent for Stein.

The results are just the latest indication that Trump's poll numbers have stalled in recent weeks. Trump on Monday fired campaign manager Corey Lewandowski after repeated infighting with campaign chairman Paul Manafort and clashes with members of Trump's family. In POLITICO's Battleground States average of 11 states likely to decide the general election, Clinton leads Trump 44.3 percent to 39.9 percent. Since 1960, no presidential candidate has won the election without winning two of the three states surveyed by Quinnipiac.

Quinnipiac conducted the polls via landlines and cellphones from June 8-19 in all three states, surveying 975 Florida voters with a margin of error of plus or minus 3.1 percentage points, 971 Ohio voters with a margin of error of plus or minus 3.1 percentage points and 950 Pennsylvania voters with a margin of error of plus or minus 3.2 percentage points.