Liquid chromatography has been used to track the concentration of remdesivir (a broad-spectrum antiviral drug, structure shown at right) in COVID patients undergoing experimental treatments. Intensity The authors provide the following details regarding standard solutions preparation: HN CN HO OH NH2 Remdesivir (RDV) stock solution (5000 µg/mL) was prepared by dissolving RDV drug powder using the mixture of DMSO: MeOH (30:70 v/v). The RDV working standard solutions for calibration and quality controls were prepared using methanol in concentrations of 100, 10, 1, 0.1, 0.01 µg/mL. 1, 2.5, 5, 7.5, 10, 25, 50, 75, 100, 250, 500, 1000, and 5000 ng/mL sample solutions were prepared freshly by spiking calibration standard solutions into the blank human plasma samples for method calibration. a) What type of calibration method is being described? Why do you think the authors chose this method as opposed to another? b) Based on the details provided in part a, describe an appropriate method blank for this analysis. 25000 20000- (b) Spiked (a) Unspiked The authors provide the following details regarding the chromatographic analysis of remdesivir: A C18 column (150 x 4.6 mm, 3 um stationary phase particles) was utilized for the separation of RDV. The mobile phase A used was 0.05% (v/v) formic acid in ultrapure water, and mobile phase B was 100% ACN with isocratic elution (A: B) 52:48 % with the total analysis time of 10 min. The column flow rate was set at 0.5 mL/min with 35 °C as the ideal column temperature, and the sample injection volume was 5 μL. 15000- 10000 5000- 0 RDV/RT 5.65 min (b) www (a) T T T 2 3 4 5 6 7 8 9 10 Retention time (minutes) c) What is one parameter you could change to decrease the retention time of RDV? Explain the theory that supports why this would work. d) What is one parameter you could change that would decrease the peak width of RDV? Explain the theory that supports why this would work.

6-54 An industrial wastewater contains 3.60 ppb cadmium Cd2+. How many mg of Cd2+ could be recovered from a ton (1016 kg) of this wastewater?

Calicheamicin gamma-1, C55H74IN3O21S4, is one of the mostpotent antibiotics known: one molecule kills one bacterialcell. Describe how you would (carefully!) prepare 25.00 mLof an aqueous calicheamicin gamma-1 solution that couldkill 1.0 x108 bacteria, starting from a 5.00 x 10-9M stocksolution of the antibiotic.

ythos.content.blackboardcdn.com/5af05a7aa8cfe/3542526?X-Blackboard-Expiration=1614816000000&X-E 100% Suppose you dissolve 4.50 g of NAOH in 500. mL of methanol, which has a density of 0.791 g/mL. The solution has a total volume of 505. mL. Find the: moles solute (a) Molarity = Liters of solution moles solute (b) Mole fraction= moles solute plus moles solvent moles solute (c) Molality= kg solvent (d) Mass % solute= mass solute X 100 mass of solute plus mass of solvent (e) ppm = Parts per million= mass solute X 1,000,000 mass of solute plus mass of solvent 18 HB #2

You have a 0.50M stock of glucose, a 150mM stock of asparagine, and a 0.05M stock of NaH2PO4, and magnesium chloride powder (solid form), MgCl2 (formula weight: 95.21g/mole). How would you prepare (be specific) 25mL of a solution that contains 0.05M glucose, 15mM asparagine, 2.5mM NaH2PO4 and 50mM MgCl2?

(12) At a given temperature the vapor pressures of benzene and toluene are 183 mm Hg and 59.2 mm Hg, respectively. Calculate the total vapor pressure over a solution of benzene and toluene with Xbenzene = 0.580. A) 106 mm Hg B) 121 mm Hg C) 131 mm Hg D) 242 mm Hg E) 262 mm Hg

> EL session.masteringchemistry.com MasteringChemistry ROSTER-2019-SPRI-PULLM-CHEM-101 blackboard wsu Google Search MasteringChemistry: HW 8 KHW 8 Applications for Dilution Calculations K8 of8 Dilution as a procedure in analysis We sometimes purposely dilute solutions if the analyte concentrations wavelengths in the visible (and sometimes uitraviolet) range. Based on the dissolved solute's properties, we can quantify that solute's concentration are too high to permit an accurate measurement. For example, a spectrophotometer can measure the amount of light that passes through a sample solution for If the solute's concentration is too high, a relatively small amount of incident light having the wavelength that corresponds to the solute's absorption behavior will less light is absorbed, and the detector in the spectrophotometer can generate more reliable data. reach the dete ctor, which results in an inaccurate measurement (consider the result if you blocked the light with an opaque…

Indicate the appropriate protocol below to prepare the required solution. a) Solution 5 Preparation: Prepare: 10 mL of 23% mannitol From: solid mannitol Procedure:  b)  Solution 2 Preparation: Prepare: 0.5 liters of 0.01 mg/mL ascorbic acid From: solid ascorbic acid , MW = 176.1 g/mol Procedure: C) Solution 3 Preparation: Prepare: 1 liter of 150 mM Tris From: 1 Molar Tris stock solution Procedure:

mass/ - H. Hm X180) d x 100 (Q16) What is the mass percent of NaCIO in 0.97M bleach sample? (Molar mass of NaCIO=74.5 g/mol, density of bleach solution= 1.08 g/mL) A) 0.73 % B) 7.2% C) 0.070 % D) 6.7% E) 0.97% the molar mass of a volatile liquid experiment, if the pressure reading from the

Density of solution:Trial 1: 1.2 g/mLTrial 2: 1.2 g/mLTrial 3: 1.2 g/mL Average density = 1.2 g/mL What is the relative average deviaion, %?