Hello mandy
Deet based mosquito repellents are known to offer the longest duration against mosquito bites as opposed to soy-bean and IR. Thus as an individual on the ground, I'd recommend a deet based repellent of a higher percentage concentration. A 20% concentration should give you about five hours of protection.
Disclaimer: The information above is based on my on experiences and does not whatsoever constitute a professional medical assessment.
Thanks.