5. ReagentsFor the analysis, reagents of analytic grade and distilled or demineralized water must be used. The formaldehyde content is determined photometry after the Acetylaceton method. Nevertheless, other procedures should be allowed if they correspond in specifications to the reference procedure for the analysis5. 1 Acetylaceton p. a.5. 2 Ammonium acetate p. a.Remark: Commercially pre-prepared solutions can be used when theidentical result is achieved.