An instrumentation for detection of nitric oxide $\left(\mathrm{NO}\right)$ by direct absorption spectrometry in the parts in ${10}^9$ (ppb) range on its electronic $X^2\mathrm{\Pi }({\nu }^{″}=0)-A^2{\mathrm{\Sigma }}^{+}({\nu }^{\prime }=0)$ transition has been constructed around a commercially available fully diode-laser-based laser system producing milliwatts powers of ultraviolet light at $\sim 226.6\mathrm{nm}$ , and its analytical performance has been evaluated. It is shown that the system is capable of detecting $\mathrm{NO}$ down to $3\mathrm{ppb}\bullet \mathrm{m}$ under low-pressure conditions (at a signal-to-noise ratio of 3 for a signal averaging of $5\mathrm{s}$ ), which is 2 orders of magnitude below that of any other diode-laser-based absorption technique. The combined line strength of the targeted lines was assessed to $3.1\times {10}^{-18}{\mathrm{cm}}^{-1}∕\left(\mathrm{molecule}{\mathrm{cm}}^{-2}\right)$ , which supersedes typical line strengths of the fundamental vibrational band and the first and second overtone bands of $\mathrm{NO}$ by $\sim 2$ , $\sim 4$ , and $\sim 5$ orders of magnitude, respectively. Also the collision broadening and shift of the targeted lines in $\mathrm{NO}$ by ${\mathrm{N}}_2$ have been assessed.