Page 9 - วิธีวิเคราะห์ไนเตรทอย่างง่ายในห้องปฏิบัติการด้วยน้ำยาสกัด Mehlich I

ห้องสมุดกรมพัฒนาที่ดิน

2

Abstract

The purpose of this research is to study the optimal reaction conditions for nitrate

analysis, test the validity of nitrate analysis in the laboratory and comparison of the
nitrate concentration using standard colour solution and the nitrate concentration using
and UV-Vis Spectrophotometer in soil samples with pH values in the range of 3.5-8.4
using Mehlich I as soil extractor. The results demonstrated that the optimal reaction

conditions were found to be 5 mL of soil solution, reagent A 0.5 mL, mixed powder
0.02 g and complete task took 5 minutes. The precision of the method was checked
by a relative standard deviation (% RSD) which was less than the maximum allowable
limit (RSD% < 10) with acceptance 95 percent. The comparison of the nitrate

concentration using standard colour solution and the nitrate concentration using and
UV-Vis Spectrophotometer showed that the accuracy was 87 percent. The study of
simple nitrate analysis methods in laboratories using Mehlich I extraction solution and

standard colour solution is an effective method as it is easy. These discover will be
useful for a rapid nitrate test kit development.