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Method for detecting concentration of lead, chromium and cadmium in tap water

A tap water and concentration technology, applied in the direction of color/spectral characteristic measurement, etc., can solve problems such as inability to determine the exact result of the detection sample, affect work efficiency, and long detection time, so as to improve detection efficiency, improve accuracy, and reduce work volume effect

Inactive Publication Date: 2019-03-05
INNER MONGOLIA MENGNIU DAIRY IND (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, the detection of heavy metals lead, chromium and cadmium in tap water is carried out according to the national standard GB / T 5750.6-2006 "Metal Indicators of Standard Inspection Methods for Drinking Water". However, when using this national standard to detect lead, chromium and cadmium, different Different pre-treatments are required for different elements, and different testing equipment is required. The detection time is long and the cost is high, which seriously affects the work efficiency; In a polyethylene container, the storage method is to add nitric acid, pH≤2
However, in the actual samples sent for inspection, some samples were not preserved with nitric acid, which caused the container to absorb heavy metal elements and affect the test results. Although nitric acid was added to some samples, the volume of nitric acid was not reflected, and the accurate results of the test samples could not be determined.

Method used

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  • Method for detecting concentration of lead, chromium and cadmium in tap water
  • Method for detecting concentration of lead, chromium and cadmium in tap water
  • Method for detecting concentration of lead, chromium and cadmium in tap water

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] Detection of lead, chromium and cadmium concentrations in tap water samples

[0073] (1) Instruments and reagents

[0074] Equipment: Graphite Furnace Atomic Absorption Spectrophotometer (Thermo ICE3500AA system), 1 / 10,000th balance.

[0075] Utensils: volumetric flask, graduated straw, pipette gun (all utensils in the experiment were soaked in (1:1) nitric acid solution overnight, then rinsed with tertiary water and ultrapure water, and then dried for later use).

[0076] Pharmaceutical reagents: nitric acid (excellent grade); nitric acid solution (1%); matrix modifier (ammonium dihydrogen phosphate solution (20g / L) + magnesium nitrate solution (1g / L)). Unless otherwise stated, the reagents used in this example were of analytical grade, and the water was ultrapure water.

[0077] (2) Detection steps

[0078] 1) Take a tap water sample, and add nitric acid to the tap water sample to prepare tap water to be tested containing 1% nitric acid.

[0079] 2) Adopt 1% ​​nit...

Embodiment 2

[0091] Determination of spiked recoveries of lead, chromium, and cadmium in tap water.

[0092] (1) Instruments and reagents are the same as in Example 1.

[0093] (2) Detection steps

[0094] 1) Take a tap water sample, and add nitric acid to the tap water sample to prepare tap water to be tested containing 1% nitric acid.

[0095] 2) Dilute 50 μL of 5 μg / mL lead standard to 100 mL, 20 μL of 5 μg / mL chromium standard to 100 mL, and 50 μL of 1 μg / mL chromium standard to 100 mL with tap water, and add appropriate amount of nitric acid, In order to obtain three kinds of spiked tap water samples containing 1% nitric acid, specifically: the tap water sample spiked with 2.5 ng / mL lead, the tap water sample spiked with 1 ng / mL chromium, and the tap water sample spiked with 0.5 ng / mL of cadmium spiked tap water to be tested.

[0096] 3) according to the method measurement step 2 of embodiment 1, the content of lead, chromium, cadmium in three kinds of standard-added tap water samp...

Embodiment 3

[0102] Determination of spiked recoveries of lead, chromium, and cadmium in tap water.

[0103] (1) Instruments and reagents are the same as in Example 1.

[0104] (2) detection procedure is the same as embodiment 2, and difference is that in the lead spiked tap water test sample that obtains, the lead spiked concentration is 5ng / mL, the chromium spiked tap water sample to be tested has a chromium spiked concentration of 2ng / mL 1. The cadmium spiked concentration in the tap water to be tested is 1 ng / mL. The test results are shown in Table 9.

[0105] Table 9 The recovery rate of standard addition of lead, chromium and cadmium in tap water to be tested

[0106]

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Abstract

The invention discloses a method for detecting the concentration of lead, chromium and cadmium in tap water. The method includes the steps: (1) taking a tap water sample, adding nitric acid into the tap water sample to prepare tap water with 1% nitric acid to be detected; (2) preparing mixed standard solution containing lead, chromium and cadmium by the aid of 1% nitric acid solution; (3) detecting the lead, the chromium and the cadmium in the tap water to be detected and first to fifth mixed standard solution by the aid of a graphite furnace atomic absorption spectrophotometer to obtain absorbance values of the lead, the chromium and the cadmium in the tap water to be detected and the first to fifth mixed standard solution; (4) drawing a lead standard curve, a chromium standard curve anda cadmium standard curve according to the absorbance values of the lead, the chromium and the cadmium in the first to fifth mixed standard solution, and calculating the concentration of the lead, thechromium and the cadmium in the tap water to be detected. The mixed standard solution includes the first to fifth mixed standard solution with the concentration from low to high. By the method, the concentration of the lead, the chromium and the cadmium in the tap water can be rapidly and accurately measured.

Description

technical field [0001] The invention belongs to the field of food, in particular, the invention relates to a method for detecting the concentrations of lead, chromium and cadmium in tap water. Background technique [0002] At present, the detection of heavy metals lead, chromium and cadmium in tap water is carried out according to the national standard GB / T 5750.6-2006 "Metal Indicators of Standard Inspection Methods for Drinking Water". However, when using this national standard to detect lead, chromium and cadmium, different Different pre-treatments are required for different elements, and different testing equipment is required. The detection time is long and the cost is high, which seriously affects the work efficiency; In polyethylene containers, the storage method is to add nitric acid, pH≤2. However, in the actual samples submitted for inspection, some samples were not preserved with nitric acid, which caused the container to absorb heavy metal elements and affect th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/31
CPCG01N21/31
Inventor 胡媛杨志伟丁勇宝李慧娟
Owner INNER MONGOLIA MENGNIU DAIRY IND (GRP) CO LTD