Portable soil heavy metal analyzer

Portable soil heavy metal analyzerUsing the national standard (GB/T50091.1-2003) borohydride/compound reduction colorimetric method, the sample is digested and then potassium iodide thiourea is added and heated to reduce pentavalent arsenic to trivalent arsenic. Under acidic conditions, borohydride/potassium hydride reduces trivalent arsenic to negative trivalent, forming arsine that is introduced into the absorption solution and appears yellow. The arsenic content is determined by instrument detection.

1Soil heavy metal analyzerDetection principle:
（1） After digestion of the sample, all forms of heavy metals (including arsenic, lead, cadmium, chromium, mercury, nickel, iron, aluminum, zinc, manganese, copper, etc.) are converted into ionic forms. After adding relevant detection reagents, the color develops. Within a certain concentration range, the depth of the solution color is proportional to the content of heavy metals, following the Lambert Beer law. The content value is then measured by instruments and compared with the national standard for the safety and quality of agricultural products and the allowable limit for pollution-free vegetable safety requirements to determine the content of heavy metals in vegetable samples.

（2） Detection principles and standards for various heavy metals
1. The detection principle and adopted standards of heavy metal arsenic
Adopting the national standard (GB/T50091.1-2003) borohydride reduction colorimetric method, the sample is digested, potassium iodide thiourea is added and heated to reduce pentavalent arsenic to trivalent arsenic, and trivalent arsenic is reduced to negative trivalent under acidic conditions to form arsine, which is introduced into the absorption solution and turns yellow. The arsenic content is determined by instrument detection.
2. The detection principle and adopted standards of heavy metal lead
The national standard (GB/T5009.12-2003) dithizone colorimetric method is adopted, which means that after digestion of the sample, under weakly alkaline conditions, lead ions form a red complex with dithizone, dissolve in chloroform, and perform colorimetric determination.
3. The detection principle and adopted standards of heavy metal chromium
After digestion of the sample, in the presence of divalent manganese, chromium ions react with diphenylcarbazide to form a purple red complex. The color of the complex is directly proportional to the hexavalent chromium content, and the chromium content can be determined by colorimetric analysis.
4. The detection principle and adopted standards of heavy metal cadmium
Using the national standard (GB/T5009.15-2003) colorimetric method, after digestion of the sample, under alkaline conditions, cadmium ions react with 6-bromophenylthiazolylazo naphthol to form a red complex, which is dissolved in chloroform for colorimetric determination.
5. The detection principle and adopted standards of heavy metal mercury
The national standard (GB/T5009.17-2003) dithizone colorimetric method is adopted, which means that after digestion of the sample, under acidic conditions, mercury ions form an orange red complex with dithizone, dissolve in chloroform, and perform colorimetric determination.

3、 Instrument technical specifications
1. Instrument transmittance accuracy ≥ ± 0.5%
2. Instrument repeatability ≤± 0.05%
3. Instrument stability without drift/30 minutes (after preheating the instrument for 5 minutes)
4. Linear error ≤ 0.2%
4. Instrument power consumption ≤ 5W
5. Power supply AC220V/50Hz or DC12V
6. The built-in new thermal printer can automatically print out the detection results, which is convenient and intuitive.
7. Size 43 × 35 × 20cm
8. Host weight 5.2kg
4Portable soil heavy metal analyzerMeasurement project
1. Instrument measurement items
Determination of heavy metals (lead, arsenic, chromium, cadmium, mercury, iron, zinc, manganese, copper) in soil, fertilizers, food, vegetables, and fruits.
2. Instrument expansion testing project
The instrument can be extended to measure the nutrient content of soil and fertilizers.
5Price of soil heavy metal detectorTest characteristics
1. The performance is reliable, and the working stability is 5-6 times better than the national standard JJG79-90. The repeatability reaches the index of grating spectrophotometers. It adopts microprocessor technology, microcontroller control, touch buttons, and is easy to operate.
2. The heavy metal testing adopts joint digestion and sub item testing techniques, simplifying the testing process, reducing testing time, greatly improving testing efficiency, and enhancing testing accuracy.
3. Strong scalability, this instrument can not only detect heavy metals but also expand the testing of nutrients in soil, fertilizers, and plants, making it versatile.
4. The soil heavy metal detector integrates medicine, equipment, and instruments into one, equivalent to a small laboratory with two aluminum alloy boxes, easy to carry, convenient for on-site testing, and mobile service. Suitable for grassroots testing departments to screen vegetables, fruits, and other foods containing heavy metal pollution.