A HyperTask Grooved Reservoir (P/N RES03384) was used for all sample types.
Density and evaporation rates were determined gravimetrically using a Sartorius BP211 D analytical balance. Evaporation rates were measured daily, by dispensing 100 μL of the sample into a plate, and recording the weight change in time. Day to day variation in the evaporation rates were found to be as much as 1.5% for a 1 μL water sample.
The liquid class used for all of this work ran at 20 μL/sec rate, with no air-gap and a linear curve assigned for the full range. The backlash for this HVH device (<5 μL) was determined visually, by aspirating 1 μL increments until liquid entered the tips.
All machine movements were at 100% travel speed except during the first 2 dispense steps, where a 5% retraction travel speed was used. At each sampling point (1, 2, 5, 10, 100, and 180 μL) excess sample (>5 μL) was aspirated from the reservoir. Some sample was then dispensed back to the reservoir (>5 μL) to eliminate the backlash.
To standardize the evaporation rate for each data point, data acquisition times were measured with a VWR laboratory timer. For the 180 μL sampling point, a dry plate was weighed and placed on the Sciclone deck. The timer was started when the sample began dispensing into a dry plate, and the second weight was taken 90 seconds later. For all other sampling points, the plate started wet, with at least 60 μL of sample in it. The timer was started when the first weight was taken, the plate was placed on the Sciclone deck, the protocol was run, and the plate was removed and placed on the balance. The second weight was recorded 90 seconds after the first.<