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Determination of Lead in Drinking Water (Graphite Furnace Atomic Absorption Spectrometry)

กรกฎาคม 28, 2025

1. Method Overview

After appropriate treatment, the sample is atomized in a graphite furnace, and the absorbance is measured at 283.3 nm. Within a certain concentration range, the absorbance of lead is proportional to its content, and quantification is performed by comparison with a standard series.

2. Instruments and Reagents

2.1 Instruments and Equipment

2.1.1 Testing Instruments

ชื่อ	ปริมาณ	Technical Requirements	เครื่องประดับ
Micropipette	1 each	100 μL~1000 μL, 1000 μL~5000 μL, 5~50 μL
Volumetric flask	Several	100 mL

2.1.2 Pretreatment Equipment

Serial No.	ชื่อ	ปริมาณ	Technical Requirements	เครื่องประดับ
1	Micropipette	1 each	100 μL~1000 μL, 1000 μL~5000 μL, 5~50 μL
2	Volumetric flask	Several	100 mL

2.2 Reagents

2.2.1 Reagents

Serial No.	ชื่อ	Technical Requirements	ข้อสังเกต
1	Nitric acid	MOS grade

2.3 Reference Standards

2.3.1 Stock Solutions

Serial No.	No.	ชื่อ	Technical Requirements	ข้อสังเกต
1	GBW 08619	Lead single-element solution standard substance	1000 μg/mL	National Institute of Metrology, China

3. Operational Procedures

3.1 Sample Processing

3.1.1 Preparation of Test Solution

Take 100 mL of water sample into a volumetric flask, add 0.5 mL of nitric acid, and mix well. Perform a blank test alongside the sample.

3.1.2 Preparation of Standard Solutions

Preparation of lead standard intermediate solution: Lead standard solution (1.0 μg/mL): Accurately pipette 0.1 mL of lead standard solution (1000 μg/mL) into a 100 mL volumetric flask, add 0.5 mL of nitric acid solution, dilute to the mark, and shake well.
Preparation of lead standard series: Accurately pipette 0.0, 0.1, 0.2, 0.3, and 0.4 mL of lead standard solution (1.0 μg/mL) into 10 mL volumetric flasks respectively. Add 0.5 mL of nitric acid solution to each, dilute to the mark, and obtain lead standard series solutions with concentrations of 0.0, 10.0, 20.0, 30.0, and 40.0 ng/mL.

3.2 Sample Testing

Testing Conditions Reference conditions for graphite furnace atomic absorption spectrophotometer detection

Element	Lead
Wavelength (nm)	283.3
Spectral bandwidth (nm)	0.4
Element lamp current (mA)	2.0
Background correction method	Deuterium lamp

Graphite Furnace Heating Program

Step	ขั้นตอน	Temperature (℃)	Ramp Time (s)	Hold Time (s)
1	Drying	120	10	10
2	Ashing	450	10	10
3	Atomization	1800	0	2
4	Cleaning	1900	1	2

Sample Testing Determine the absorbance of standard solutions, blank test solutions, and test solutions in sequence. Subtract the absorbance of the zero standard solution from the absorbance of each standard solution. Plot a working curve with mass concentration as the abscissa and the corresponding absorbance as the ordinate. Based on the measured absorbance of the test solution, find the mass concentration of lead from the working curve.