钾的测定涉及多种仪器，不同仪器测钾原理、仪器性能和优缺点也各不相同。本研究对电感耦合等离子光谱仪（ICP）、原子吸收分光光度计（AAS）、普通火焰光度计（FP M410型）和带锂内标的火焰光度计（FP HG-5型）等几种常用仪器测钾的检出限、线性范围、稳定性以及抗干扰能力等方面进行了比较。结果表明，ICP、AAS、FP（M410）和FP（HG-5）测钾检测限分别为0.16、0.002、0.005和0.007 mg L-1，线性范围的上限则分别为1 000、3、100和60 mg L-1。四种仪器抗酸干扰能力大小顺序为FP（HG-5） > ICP > FP（M410） > AAS，抗盐干扰的能力大小为FP（HG-5）> FP（M410）> ICP >AAS，且因盐离子种类和浓度而异。综合比较后可知，ICP适合于在测定多种其他元素的同时测定较高含量的钾，而不适合于测较低含量的钾，单独测钾成本较高；AAS适合于测较低含量的钾，线性范围窄，加锶和高钾溶液的稀释使其效率下降，而且仪器成本也较高；FP（M410）易操作，运营成本低，但易受干扰且稳定性较差；带锂内标的FP（HG-5）检测限低，稳定性能好，线性范围适中且抗酸盐干扰能力强，是精确测钾的首选仪器。
To determine potassium, there is a variety of instruments available for use, but they are quite different in working principles, performance, advantage and shortcoming. In this study, comparison was made between Inductively Coupled Plasma Spectrometer (ICP), Atomic Absorption Spectrometer (AAS), M410 Flame Photometer (FP-M410) and HG-5 Flame Photometer (FP-HG-5) in detection limit, linear range, stability and interference resistance of potassium determination. Results show that the detection limit was 0.16 mg L-1 for ICP, 0.002 mg L-1 for AAS, 0.005 mg L-1 for FP-M410 and 0.007 mg L-1 for FP-HG-5, and the maximum linear range 1 000, 3, 100 and 60 mg L-1, respectively. Their acid interference resistance followed an order of FP-HG-5 > ICP > FP-M410 > AAS, while their salt interference resistance did an order of FP（HG-5）> FP（M410）> ICP > AAS, which was subject to some variation with the type and concentration of the salt. The comprehensive comparison reveals that ICP is suitable for determination of K relatively high in concentration and a variety of other elements simultaneously, but the cost of its operation for potassium measurement alone is relatively high; AAS is suitable for determination of K relatively low in concentration with a narrow linear range, but the addition of Sr and dilution of high K solution may reduce its efficiency, and moreover its operation cost is also quite high; FP-M410 is easy to operate and low in cost, but susceptible to interference and hence low in stability; and FP-HG-5, with Li internal standard is low in detection limit, good in stability, proper in linear range and high in resistance to the interference of acids or salts, which suggests that FP-HG-5 is the first choice for accurate determination of potassium.
王 敬,王火焰,周健民,陈小琴,杜昌文.不同仪器测钾性能及优缺点比较研究[J].土壤学报,2013,50(2):340-348. DOI:10.11766/trxb201203080066 Wang Jing, Wang Huoyan, Zhou Jianmin, Chen Xiaoqin, Du Changwen. Comparison between different instruments in potassium determination performance[J]. Acta Pedologica Sinica,2013,50(2):340-348.复制