A fluid analyzer that analyzes a sample , the fluid analyzer comprising: an analyzer frame ; a first module that includes a test cell assembly that receives the sample, and a first module frame that retains the test cell assembly; wherein the test cell assembly includes (i) a cell chamber , (ii) an inlet conduit that is in fluid communication with the cell chamber; and (iii) an outlet conduit that is in fluid communication with the cell chamber; a laser assembly that generates a laser beam that is directed through the test cell assembly and the sample in the test cell assembly, the laser assembly being coupled to the analyzer frame; and a signal detector assembly that collects a test signal light transmitted through the test cell assembly, the signal detector assembly being coupled to the analyzer frame; and a first coupler assembly that releasably couples the first module frame to the analyzer frame so that the first module can be selectively removed from the analyzer frame, a beam director assembly which directs the laser beam from the laser assembly at the test cell assembly; wherein the beam director assembly includes a first optical element that is coupled to the first module frame spaced apart from the test cell assembly; and wherein the first optical element is secured to the first module frame so that the first optical element is selectively removed from the analyzer frame with the first module ; wherein the beam director assembly includes a mirror that is coupled to the first module frame spaced apart from the test cell assembly; wherein the mirror directs the test signal light transmitted through the test cell assembly at the signal detector assembly ; wherein the mirror is fixedly secured to the first module frame so that the mirror is selectively removed from the analyzer frame with the first module . an analyzer frame ; a first module that includes a test cell assembly that receives the sample, and a first module frame that retains the test cell assembly; wherein the test cell assembly includes (i) a cell chamber , (ii) an inlet conduit that is in fluid communication with the cell chamber; and (iii) an outlet conduit that is in fluid communication with the cell chamber; a laser assembly that generates a laser beam that is directed through the test cell assembly and the sample in the test cell assembly, the laser assembly being coupled to the analyzer frame; and a signal detector assembly that collects a test signal light transmitted through the test cell assembly, the signal detector assembly being coupled to the analyzer frame; and a first coupler assembly that releasably couples the first module frame to the analyzer frame so that the first module can be selectively removed from the analyzer frame, a beam director assembly which directs the laser beam from the laser assembly at the test cell assembly; wherein the beam director assembly includes a first optical element that is coupled to the first module frame spaced apart from the test cell assembly; and wherein the first optical element is secured to the first module frame so that the first optical element is selectively removed from the analyzer frame with the first module ; wherein the beam director assembly includes a mirror that is coupled to the first module frame spaced apart from the test cell assembly; wherein the mirror directs the test signal light transmitted through the test cell assembly at the signal detector assembly ; wherein the mirror is fixedly secured to the first module frame so that the mirror is selectively removed from the analyzer frame with the first module . <EOS>