The Knowledge Hub
Practical troubleshooting guides for working analytical chemists — HPLC, UHPLC, LC-MS, GC, and reagent prep. Each guide is diagnostic-first and linked to the tool that resolves it.
Drifting HPLC Peak Retention Times
A drift in analyte retention time over time is sometimes observed in HPLC chromatograms. This drift takes analytes outside their ‘retention window’…
Molarity of 50% (w/w) Sodium Hydroxide (NaOH)
Overview A 50% solution of sodium hydroxide is a clear and colorless liquid. It is available is in premade format from a…
Chromatography Terms
HPLC Column Cleaning
As HPLC chemists we know that columns do have a finite lifetime. You column life time (total number of samples you can…
Poor Gas Chromatography Peak Shapes: Troubleshooting
Poor Gas Chromatography (GC) peak shapes manifest as follows- Peak Splitting Peak Fronting Peak Tailing
Molarity of 96% (w/w) Sulfuric acid (H2SO4)
Density of H2SO4 = 1.84g/mL Molecular weight of H2SO4 is 98.079 96 ml H2SO4 equals 96 x 1.84 = 176.64 g Hence,…
Molarity of 95% (w/w) Sulfuric acid (H2SO4)
Density of H2SO4 = 1.84g/mL Molecular weight of H2SO4 = 98.079 95 ml H2SO4 equals 95 x 1.84 = 174.8 g of…
Molarity of 37% (w/w) Hydrochloric Acid (HCl)
Overview Preparation Step 1: Calculate the volume of 100 grams of Hydrochloric acid. Formula: Density = weight / volume or Volume = …
Molecular and Equivalent Weights of Common Compounds
Chemical Name Molecular Formula Molecular Weight (g/mol) Equivalent Weight (g/equiv) Acetic Acid CH3COOH 60.05 60.05 Ammonium Sulfate (NH4)2SO4 132.14 132.14 Calcium Carbonate…
Preparation of 0.25 M Sodium Hydroxide (NaOH) Solution
Overview Calculation procedure Parameter Value Required volume 1000 mL Molecular weight of NaOH 39.997 g/mole Concentration of 0.25 M Sodium Hydroxide 0.9999%…
Preparation of 2X YT Media
Overview Reagents Required Equipment Preparation Step 1: To prepare 1000 ml of 2 X YT medium, weigh out 16 g tryptone, 10…
Poor HPLC Peak Shapes: Troubleshooting
Figure 1 shows various peak shape issues and their root causes observed while running an HPLC. These peak shape issues include peak…