Spectrophotometric Estimation of Nitrazepam in Pure and in Pharmaceutical Preparations

Table 1

Optical characteristics and precision.

Parameter	Method A	Method B	Method C
λ max  (nm)	400	550	460
Linear range (μg/mL)	0.5–20	0.3–14	0.5–12
Molarabsorptivity(ε), (L mol^−1 cm^−1)	1.01 × 10^4	1.00 × 10^4	1.51 × 10^4
Sandell sensitivity (μg cm^−2)	0.0281	0.0281	0.0186
Intercept (a)	0.0194	−0.0040	0.0042
Slope (b)	0.0327	0.0365	0.0530
Correlation coefficient (r)	0.9982	0.9999	0.999
𝑆𝑎	0.0182	0.0037	0.0134
𝑆𝑏	0.0012	0.0029	0.00127
LOQ (μg/mL)	0.1550	0.1213	0.0928
LOD (μg/mL)	0.0512	0.0400	0.0306

∗y = bc + a where c is the concentration of nitrazepam in μg/mL and y is the absorbance at the respective λ _max. 𝑆_𝑎 is the standard deviation of intercept, 𝑆_𝑏 is the standard deviation of slope.