firstly, you convert litres to m^3 (1000 litres = 1m^3) Then you multiply the volume (m^3) by the density of the fluid and you devide the result by 60. Big man, this is the way for sure... trust me
Standard Liter per minute (SLPM) refers to the flow rate of a gas at "standard conditions" (usually sea level pressure, room temperature..etc)Liter per minute (LPM) is the flow rate at the conditions...
1 microgram = 1 millionth of a gram or .000001 - so, just move the decimal point over to the appropriate position. As long as you don't change the value of the number, you can do what you want to it.