钢铁及铁合金中碳的测定,目前多用燃烧-气体容积法。近年也有高速定碳电导法、导磁校正法等,但这些方法一般均要特殊仪器,有些也不适于低碳的测定。钢铁中低碳的测定,报导较多,有用氢氧化钠吸收燃烧过程中释出的二氧化碳,用茜素黄R或水杨基黄的比色测定法;有用氢氧化钡吸收二氧化碳,以铬黑T Determination of carbon in steel and iron alloy, the current multi-purpose combustion - gas volumetric method. In recent years, there are also high-speed constant carbon conductivity method, magnetic flux correction method, but these methods generally require special equipment, and some are not suitable for low-carbon determination. Determination of low-carbon steel, reported more useful sodium hydroxide to absorb carbon dioxide released during combustion, with alizarin yellow R or salicylic yellow colorimetric assay; use of barium hydroxide to absorb carbon dioxide to chromium black T