Table 4 Comparison and assessment of published and proposed spectrofluorimetric for the estimation of PGB using principles of green and white analytical chemistry
Types of spectrofluorimetric method | Analytical conditions | Sensitivity, whiteness and greenness profile assessment of methods |
|---|---|---|
Method 1—Spectrofluorimetric estimation of PBG using 7-chloro-4-nitrobenzofurazon (NBD-Cl) as fluorescent probe [22] | Linearity—40 to 400 ng/mL Derivatization agent—7-chloro-4-nitrobenzofurazon (NBD-Cl) Excitation wavelength—460 nm Emission wavelength—558 nm Extraction solvent—Chloroform (More than 10 mL) Reaction temperature—60 to 80˚C Application—Assay of marketed formulations | The method includes toxic organic solvents and reagents. The reaction temperature is more than room temperature The method has sensitivity as nanogram level AGREE score: 0.55 GAPI e-factor: 0.5 ESA penalty points: 08 Red model s score—100/100 Green model score—55/100 Blue model score—90/100 Whiteness score—(100 + 55 + 90)/3 = 81.66 |
Method 2—Spectrofluorimetric estimation of PGB using fluorescamine, 2,4-dinitrofluorobenzene and chloranil as fluorescent probes [23] | Linearity—20 to 280 ng/mL Derivatization agent—Fluorescamine, 2,4-dinitrofluorobenzene and chloranil Excitation wavelength—385 nm Emission wavelength—485 nm Extraction solvent—Water Reaction temperature—60 to 80˚C Application—Assay of marketed formulations and bioanalysis of spiked urine samples | The method needs toxic derivatization reagents and high temperature for reaction The method has sensitivity as nanogram level AGREE score: 0.60 GAPI e-factor: 0.50 ESA penalty points: 06 Red model s score—100/100 Green model score—60/100 Blue model score—90/100 Whiteness score—(100 + 60 + 90)/3 = 83.33 |
Method 3—Spectrofluorimetric estimation of PGB using fluorescamine as fluorescent probe [24] | Linearity—0.01 to 0.3 µg/mL Derivatization agent—Fluorescamine Excitation wavelength—390 nm Emission wavelength—487 nm Extraction solvent—Water Reaction temperature—60 to 80˚C Application—Assay of marketed formulations | The method needs toxic derivatization reagents and high temperature for reaction The method has sensitivity as micro and nanogram level AGREE score: 0.65 GAPI e-factor: 0.35 ESA penalty points: 06 Red model s score—95/100 Green model score—65/100 Blue model score—90/100 Whiteness score—(95 + 65 + 90)/3 = 83.33 |
Method 4—Spectrofluorimetric estimation of PGB using carbon quantum dots [26] | Linearity—4 to 100 µg/mL Derivatization agent—Carbon quantum dots from ascorbic acid Excitation wavelength—356 nm Emission wavelength—524 nm Extraction solvent—Water Reaction temperature—160˚C, 70 min Application—Assay of marketed formulations and bioanalysis of spiked urine sample | The method needs toxic reagents and very high temperature for reaction The method has sensitivity as microgram level only AGREE score: 0.65 GAPI e-factor: 0.35 ESA penalty points: 06 Red model s score—95/100 Green model score—65/100 Blue model score—90/100 Whiteness score—(95 + 65 + 90)/3 = 83.33 |
Method 5—Spectrofluorimetric estimation of PGB using acetylbutyrolactone as fluorescent probe [27] | Linearity—10 to 100 µg/mL Derivatization agent—Acetylbutyrolactone Excitation wavelength—380 nm Emission wavelength—440 nm Extraction solvent—Water Reaction temperature—95˚C Application—Assay of marketed formulations | The method needs toxic derivatization reagents and high temperature for reaction The method has sensitivity as microgram level only AGREE score: 0.65 GAPI e-factor: 0.35 ESA penalty points: 06 Red model s score—95/100 Green model score—65/100 Blue model score—90/100 Whiteness score—(95 + 65 + 90)/3 = 83.33 |
Proposed spectrofluorimetric estimation of PGB | Linearity—10 to 250 ng/mL Derivatization agent—No reagent Excitation wavelength—230 nm Emission wavelength—410 nm Extraction solvent—Water Reaction temperature—25˚C (Room Temperature) Application—Assay of marketed formulations | No chemical reaction required and water is used as solvent The method has sensitivity at nanogram level. The method does not require heating. Hence, it is more user-friendly AGREE score: 0.80 GAPI e-factor: 0.25 ESA penalty points: 03 Red model s score—100/100 Green model score—80/100 Blue model score—100/100 Whiteness score—(100 + 80 + 100)/3 = 93.33 |