Yes, you can do seated wide grip barbell curl. The best way to do it is using all 3 sitting positions, that is, start on a 70-degree hip angle and perform your regular wide grip seated curls with a 50 rep cadence. Then rotate your hips (like you are going to stand up) and sit back down but this time at 30 degrees hip angle doing another 30 reps of the seated wide grip barbell curl.