For GC analysis, the following can cause band broadening and poorresolutionUse of automatic samplerSlow injection and oversize samplesUse of 5 m or longer packed columnFor samples of fatty acid methyl esters, alkaloids, drugs, andhalogenated compounds, an applicable liquid stationary phase for GLCisPolyethylene glycol50% Cyanopropyl-polydimethyl siloxane5% Phenyl-polydimethyl siloxaneA C18 column is an example of a "reverse phase" column. Reverse phasecolumns are often used with more polar solvents such as water,methanol or acetonitrile. The stationary phase is a nonpolarhydrocarbon, whereas the mobile phase is a polar liquid. If a sample hasthe following components, what will be the order of elution? (A.) 1,6-Hexadiol (B.) 2,5-Hexadiol (C.) 2,3,4-HexatriolCBABCAABC

Chromatography is separating technique for mixtures into it's components. It is based on the…

For GC analysis, the following can cause band broadening and poor resolution OUse of automatic sampler Slow injection and oversize samples O Use of 5 m or longer packed column For samples of fatty acid methyl esters, alkaloids, drugs, and halogenated compounds, an applicable liquid stationary phase for GLC is Polyethylene glycol 50% Cyanopropyl-polydimethyl siloxane 5% Phenyl-polydimethyl siloxane

For GC analysis, the following can cause band broadening and poor resolution OUse of automatic sampler Slow injection and oversize samples O Use of 5 m or longer packed column For samples of fatty acid methyl esters, alkaloids, drugs, and halogenated compounds, an applicable liquid stationary phase for GLC is Polyethylene glycol 50% Cyanopropyl-polydimethyl siloxane 5% Phenyl-polydimethyl siloxane

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter31: Introduction To Analytical Separations

Section: Chapter Questions

Problem 31.32QAP

See similar textbooks

Similar questions

functional grp analysis compound: myristic acidpls complete the table Test Reagent Observation Inference NaHCO3 Effervescence Br2 in water, dark Yellow solution 2,4-DNPH Orange solution KMnO4 Purple solution
A mixture of biphenyl, benzyl alcohol, and benzoic acid is spotted on a silica gel TLC plate and developed using Ethyl Acetate with 0.5% acetic acid as the solvent. Predict the relative Rf (highest to lowest).
(i) Calculate the capacity factors (k') for both compounds A and B and the selectivity factor (a) between them, commenting on the values. (ii) Calculate the resolution between A and B and comment on it. (iii) Using the peak for A, calculate the number of theoretical plates for the GC column and comment on the quality of the column.
Despite their structural differences, separation of mixtures of organic compounds (such as the arenes benzoic acid, 4-t-butylphenol, and benzamide) often proves difficult. Silica gel chromatography, however, can be used with some success provided that an appropriate solvent is used to provide optimal separation. Consider, for example, the TLC plate pictured at right after developing and UV visualization where prior to elution, lanes A and B were spotted with 4-t-butylphenol and lanes B and C spotted with benzamide. Which of the following must be true? In the space provided, indicate the CORRECT answers (as 1, 2, and/or 3) then explain your reasoning for all three statements. Benzamide elutes faster than t-butylphenol. The Rf for t-butylphenol is less than that of benzamide. Benzamide is more polar than 4-t-butylphenol
A 5.00-mL sample of blood was treated with trichloroacetic acid to precipitate proteins. After centrifugation, the resulting solution was brought to pH 3 and extracted with two 5-mL portions of methyl isobutyl ketone containing the lead-complexing agent APCD. The extract was aspirated directly into an air/acetylene flame and yielded an absorbance of 0.569 at 283.3 nm. Five-milliliter aliquots of standard solutions containing 0.400 and 0.600 ppm of lead were treated in the same way and yielded absorbances of 0.396 and 0.599. Please calculate the concentration of lead in the sample in ppm.
A 5.00-mL sample of blood was treated with trichloroacetic acid to precipitate proteins. After centrifugation, the resulting solution was brought to pH 3 and extracted with two 5-mL portions of methyl isobutyl ketone containing the lead-complexing agent APCD. The extract was aspirated directly into an air/acetylene flame and yielded an absorbance of 0.527 at 283.3 nm. Five-milliliter aliquots of standard solutions containing 0.400 and 0.600 ppm of lead were treated in the same way and yielded absorbances of 0.396 and 0.599. Find the concentration of lead in the sample in ppm assuming that Beer’s law is followed.
1. Discuss briefly the specifications and test parameters for system suitability for HPLC analysis.
Calculate the amount of phycocyanin in Sample 1 in mg where A620 = 0.193 and A650 = 0.095, taking into account the dilution factor of 100 ul, and the total volume of extract 45ml. Note your answer to 2 decimal places.
percentage recovery of benzoic acid is 77.18%. The melting point range of crude benzoic acid = 112-119°C and the melting point range of pure benzoic acid (crystals) = 122-125. Comment on the percentage recovery of benzoic acid. Comment and compare the melting point of the crude and crystal samples
The following is an HPLC separation of deuterated benzenes on a C18 column that 440 cm long. The mobile phase was 30% acetonitrile:70% water at 30oC. What is the mobile phase velocity? Find the retention factor k' for C6D6. Find the plate number and plate height for C6D6.. Assuming that the peak widths for C6H5D and C6H6 are the same as that of C6D6., find the resolution for C6H5D and C6H6. Retention times for C6H5D and C6H6 are 193.3 and 194.3 respectively, Find the relative retention time and unadjusted relative retention time between C6H5D and C6H6.
In HPLC, why is purging or initialization being done before analysis of samples, explain.
In order to improve the peptide separation by using a HPLC system, trifluoroacetic acid acts as mobile-phase modifier was added during the preparation of mobile phase. The preparation was performed by a postgraduate student as following:“2.851 g trifluoroacetic acid (MW: 114.02 g/mol) was made up to 500 cm3 in a graduated flask. To this solution, 50 cm3 of ethanol was added, and after mixing the mobile phase was placed in the solvent reservoir and pumping was commenced at 1.5 cm3 min-1.”Based on the given preparation procedure, identify THREE mistakes that were made.