Tester for Pesticide residues introduction 1
Testing Principle
After digestion to the sample , all metals (Arsenic, Lead,Mercury, Cadmium, Chromium) are into ionic form , heavy metal
and dithizone solution can form purple solution in near-neutralconditions . Solution color is proportional with content of
heavy metal in a certain concentration range , it obey“ Lambert-Beer Law “ :
E＝K*C*L
E：Extinction; K：Extinction Coefficient; C： SolutionConcentration; L： Solution Thickness .
We can get : C=E/KL
Suppose solution to be tested is C2，if K，L is same,
Then , C2=E2/E1*C1
We can get E2/E1 from instrument test ， C1 is standardsolution ，when we input C1 ，instrument can calculate and
display C2 automatically .
B、Technical Index :
1，Stability : displayed number(transmittance measurement) drift is less than 0.7 % (A) , within 3
minutes after powering on for 20 minutes .
2，Sensitivity : Kλ≥3.4×10-3 , （testing in Potassium dichromate standard solution）.
3，Repeatability : error ≤ 0.003 (A) , （testing in Potassium dichromate standard solution）.
4，Linear error : Absorbance range : 0.1～0.3，linear error ≤±6% ；0.3～0.6 , linear error : ≤
±4% ；0.6～0.8，linear error ≤ ±5%（testing in Potassium dichromate standard solution） .
1. Power consumption : ≤ 5W .
2. Cultivate heating power : ≤ 100W .
C、Testing Items :
1. Heavy metal in the food .
2. Pesticide residue in the food .
Nitrate and nitrite in the food .
Formaldehyde, sulfoxylate, Sulfur dioxide
