In one or more embodiments, there is a dual syringe for the collection of fluid samples which enables taking two distinct samples, and a method of use thereof. Preferably the dual syringe is for single use. Generally, the dual syringe has three components: an outer barrel; an inner barrel that fits inside the outer barrel, locks to the outer barrel and has a rubber fitting on its tip so it can function as a plunger for the outer barrel; and a plunger for the inner barrel. There is a one-way valve in a nozzle opening or passage of the inner syringe enabling inward flow only. In a method of use, an initial portion of sample fluid, e.g., from a sampling port of a bioreactor vessel, is drawn into the inner barrel of the device by pulling on the plunger. The one-way valve prevents backflow of that initial portion of sample fluid thereby protecting the ideally aseptic chamber of the outer barrel. A subsequent sample can then be collected in the outer barrel without the two samples by overcoming or otherwise unlocking the inner barrel from the outer barrel, and pulling on the inner barrel. The sample in the outer barrel is distinct from the sample in the inner barrel. Each barrel can establish direct communication with the device tip, allowing the user to draw two distinct samples that do not interact with each other.