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 (240E, 1440F) that is coupled to the first module frame spaced apart from the test cell assembly; and wherein the first optical element (240E, 1440F) is secured to the first module frame so that the first optical element (240E, 1440F) 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 (240E, 1440F) that is coupled to the first module frame spaced apart from the test cell assembly; and wherein the first optical element (240E, 1440F) is secured to the first module frame so that the first optical element (240E, 1440F) 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.