D'Angelo E, Crutchfield J, Vandiviere M
Univ. of Kentucky, Soil & Water Biogeochemistry Lab., Dep. of Agronomy, Lexington 40546-0091, USA.
J Environ Qual. 2001 Nov-Dec;30(6):2206-9. doi: 10.2134/jeq2001.2206.
A rapid and sensitive analysis of inorganic and organic phosphorus (P) is needed to analyze water and soil extracts at submicromolar concentrations. The proposed method, based on the complexation of malachite green with phosphomolybdate under acidic conditions, was adapted to a 96-well microtiter plate format, and was tested for matrix interferences using 15 soils and some common extractants, including water, KCI, CaCl2, NaOH, and HCl. The accuracy of P determination was affected when CaCl2 and HCl concentrations were greater than 0.1 M and when NaOH concentration exceeded 0.4 M. Potassium chloride concentration up to 1 M did not interfere with P determination. The molar absorptivity was 46 841 M(-1) cm(-1) and the reagent blank absorbance was 0.071+/-0.003 (n = 10). At the 99% confidence limit, the method detection limit was calculated to be 0.006 mg P L(-1). Recovery of added inorganic P in different types of soils and extracts ranged between 95 and 112% with an average of 102%. The proposed microplate method allows P to be determined rapidly in a wide range of soil types and extracts and requires limited volume (20-200 microL). The procedure uses limited quantities (40 microL) of two stable reagents (>1 yr), and generates low amounts of hazardous waste.
为了分析亚微摩尔浓度下的水和土壤提取物，需要对无机磷和有机磷（P）进行快速灵敏的分析。所提出的方法基于孔雀石绿与磷钼酸盐在酸性条件下的络合反应，采用96孔微量滴定板形式，并使用15种土壤和一些常见提取剂（包括水、氯化钾、氯化钙、氢氧化钠和盐酸）测试了基质干扰。当氯化钙和盐酸浓度大于0.1 M以及氢氧化钠浓度超过0.4 M时，磷测定的准确性会受到影响。高达1 M的氯化钾浓度不会干扰磷的测定。摩尔吸光系数为46841 M⁻¹ cm⁻¹，试剂空白吸光度为0.071±0.003（n = 10）。在99%置信限下，该方法的检测限经计算为0.006 mg P L⁻¹。不同类型土壤和提取物中添加的无机磷回收率在95%至112%之间，平均为102%。所提出的微孔板方法能够在多种土壤类型和提取物中快速测定磷，所需体积有限（20 - 200 μL）。该方法使用限量（40 μL）的两种稳定试剂（保质期>1年），且产生的有害废物量较少。
