Parameters

Method I

Method II

Method III

Method IV

Current method

Reagent

Ninhydrin in methanol

Potassium iodate and potassium iodide

1, 2-napthaquinone-4- sulfonic acid sodium

4-chloro-7-nitrobenzo- 2-oxa-1, 3-diazole

Henna as extract

Wave length (nm)

578

352

475

390

410

Beer’s law limits (μg·ml⁻¹)

5 - 50

10 - 50

10 - 100

5 - 25

35 - 100

Correlation coefficient (R²)

0.9994

0.9994

0.993

0.9998

0.996

LOD (μg/ml)

1.08

0.41

10

0.29

7.4

LOQ (μg/ml)

3.58

1.25

100

0.88

22.4

References

Proposed method