Monthly Archives: June 2011
Two Ways to Prepare a Standard Addition
The illustration below shows one method for making a standard addition. The volumetric flask on the left contains a portion of the sample, Vo, and the volumetric flask on the right contains an identical portion of the sample and a … Continue reading
GC Columns
The photo below shows a typical example of a packed column for gas chromatography. This column is made from stainless steel and is 2 m long with an internal diameter of 3.2 mm. The packing material in this column has … Continue reading
GC Detectors
Shown below is a schematic diagram of a thermal conductivity detector. This is one of a matched pair of cells. The sample cell takes the carrier gas as it elutes from the column. A source of carrier gas that bypasses … Continue reading
GC Injectors
Shown below is a schematic diagram of a heated GC injector port for use with a packed column. The needle pierces a rubber septum and enters into the top of the column, which is located within a heater block. Show … Continue reading
External Standards Calibration Curve
Shown at the top is a reagent blank (far left) and a set of five external standards for Cu2+ with concentrations increasing from left to right. Shown below the external standards is the resulting normal calibration curve. The absorbance of … Continue reading
Standard Addition Calibration Curve
Shown at the top is a set of six standard additions for the determination of Mn2+. The flask on the left is a 25.00-mL sample diluted to 50.00 mL. The remaining flasks contain 25.00 mL of sample and, from left … Continue reading