A typical HPLC column is 15.0 cm long and 4.6 mm in diameter. What is the internal volume of the column? What is the volume of a 5-μm diameter particle (approximate it as a hard sphere)? Because of the way spherical particles pack in a column, the volume that is external to the particles is approximately 40% of the entire column volume, meaning that 60% of the column volume is occupied by the particles. Given this, the total column volume you calculated in part (a), and the volume of a particle you calculated in part (b), calculate the number of particles packed in a 15.0 cm x 4.6 mm column

What are the differences between systematic and random errors and how do they effect accuracy and precision?   In what circumstances would you use standard addition (versus a normal calibration curve) to determine the amount of an analyte in a sample?   A urine sample, containing analyte Z is analysed by the standard addition method where 5 mL of the original sample was mixed with increasing amounts of a Z standard and each solution diluted to a volume of 50 mL prior to analysis. A plot of the final concentration of the standard in each of the 50 mL samples (x axis) versus   The measured signal from the analysis of each 50 mL sample (on y axis) produced a straight line with the general equation:   y = 44.72x + 4.06   what was the final concentration of Z in the 50 mL standard addition sample? what was the initial concentration of Z in the original urine sample?

Quantitative Analysis by External Standard Method Calcium in a juice sample is determined by atomic absorption spectrophotometry. A stock solution of calcium is prepared by dissolving 1.834 g of CaCl, 2H20 in water and diluting to 1000.0 mL. A substock calcium solution was prepared by transferring 10.00 mL of the stock to a 100.00 mL volumetric flask and diluting to the mark. Three standard solutions of calcium were prepared by transferring 2.500 mL. 5.00 mL and 10.00 mL of substock to 50.00 mL volumetric flasks and diluting to the mark. The sample is prepared by transferring 1.000 mL of fruit juice from the original bottle to a 25.00 mL flask and diluting to the mark. Strontium chloride is added to all solutions before dilution to avoid phosphate interference. Instrumental response of the standards is measured against the blank, and the following readings are recorded: 9.10, 18.6 and 37.0. The sampie reading is 28.1. Using the multipoint method, find the concentration of calcium in…

A peak elutes from an HPLC column 13.8 cm in length in 14.8 min. What would be the width at half-height of the peak (in seconds) if the plate height were 7.75 µm? W 1/2 = What would be the width at half-height of the peak (in seconds) if the plate height were 46.0 μµm? W 1/2 = S S