I solve this problem.

I was leaved ADCON1 and ADCON0 to unchanged. I changed sampling time to 50us and ADC clock to 3. Now working each channel independed from other.

I use Mister E PIC multi-calc and A/D calc menu. I don't understand how calculate input impedance?
I have 3 trimmer resistor 10K on each channel. How is then 30k input impedance or 10K in my case?

have someone the solution?

Thanks,
Samo