Chromatograms

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Page ID: 285021

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Analytical Sciences Digital Library

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All Analgesics, 55% pH=7 0.025M phosphate buffer

C18, Black Trace 245 nm, Green Trace 195nm

RP-Amide, Black Trace 245 nm, Green Trace 195nm

C18-PFP, Black Trace 245 nm, Green Trace 200nm

RP-Amide, 55% pH=5 0.025M phosphate buffer

Mix A (order: aspirin and caffeine, salicyclamide, phenacetin), Black Trace 245 nm, Green Trace 220nm

Acetaminophen, Black Trace 245 nm, Green Trace 195nm

Ibuprofen, Black Trace 245 nm, Green Trace 195nm

Diphenhydramine, Black Trace 245 nm, Green Trace 195nm

All Analgesics, 195nm

RP-Amide, 55% pH=7 0.025M phosphate buffer

Mix A, Black Trace 245 nm, Green Trace 220nm: aspirin, caffeine, salicyclamide, and phenacetin, respectively

Acetaminophen, Black Trace 245 nm, Green Trace 195nm

Ibuprofen, Black Trace 245 nm, Green Trace 195nm

Diphenhydramine, Black Trace 245 nm, Green Trace 195nm

All Analgesics, Black Trace 245 nm, Green Trace 195nm

RP-Amide, 55% pH=9 0.025M phosphate buffer

Mix A (order aspirin, caffeine and salicyclamide, phenacetin) Black Trace 245 nm, Green Trace 230nm

Ibuprofen, Black Trace 245 nm, Green Trace 195nm

Diphenhydramine, Black Trace 245 nm, Green Trace 195nm

All Analgesics, Black Trace 245 nm, Green Trace 200nm

C18-PFP, 55% pH=5 0.025M phosphate buffer

Mix A (aspirin, caffeine, salicyclamide, phenacetin) Black Trace 245 nm, Green Trace 213nm

Acetaminophen, Black Trace 245 nm, Green Trace 195nm

Ibuprofen, Black Trace 245 nm, Green Trace 195nm

Diphenhydramine, Black Trace 245 nm, Green Trace 195nm

All Analgesics, Black Trace 245 nm, Green Trace 195nm

C18-PFP, 55% pH=7 0.025M phosphate buffer

Mix A (order aspirin, caffeine, salicyclamide, phenacetin), Black Trace 245 nm, Green Trace 225nm

Acetaminophen, Black Trace 245 nm, Green Trace 195nm

Ibuprofen, Black Trace 245 nm, Green Trace 195nm

Diphenhydramine, Black Trace 245 nm, Green Trace 195nm

All Analgesics, Black Trace 245 nm, Green Trace 200nm

C18-PFP, 55% pH=9 0.025M phosphate buffer

Mix A (order aspirin, caffeine and salicyclamide, and phenacetin) Black Trace 245 nm, Green Trace 210nm

Ibuprofen, Black Trace 245 nm, Green Trace 195nm

Diphenhydramine, Black Trace 245 nm, Green Trace 195nm

All Analgesics, Black Trace 245 nm, Green Trace 200nm

Unknown Tablets on C18-PFP, 55% pH=7 0.025M phosphate buffer

Unknowns were crushed, dissolved in 250 mL water, and filter with 0.45 micropore filters, followed by a 1:10 dilution in methanol.

Tablet 1, Black Trace 245 nm, Green Trace 195nm

Tablet 2, Black Trace 245 nm, Green Trace 200nm

Tablet 3, Black Trace 245 nm, Green Trace 200nm

Tablet 4, Black Trace 245 nm, Green Trace 200nm

Tablet 5, Black Trace 245 nm, Green Trace 195nm

Supplemental Information

All stock solutions were made by dissolving weight listed of analgesic in 50.0 mL methanol

Stock Compounds (Amount in Stock)	pKa	Melting Point
Aspirin (acetylsalicyclic acid) 90mg	3.49	134-6˚C
Caffeine 30 mg	10.4	238˚C
Salicyclamide 90 mg	8.37	140-4˚C
Phenacetin 12 mg	2.2	133-8˚C
Acetaminophen 5 mg	9.38-9.9	169˚C
Ibuprofen 50 mg	4.91-5.2	76˚C
Diphenhydramine HCl 50 mg	9-10.10	166˚C