-
E-mail
inquire-china_lsca@agilent.com
- Phone
-
Address
No. 3 Wangjing North Road, Chaoyang District, Beijing
Agilent Technologies (China) Co., Ltd
Universal scheme for determining total fluoride content in organic fluorides by ICP-MS/MS
Date: 2025-12-16Read: 0
Development of demand-oriented approach
In recent years, the demand for detection of PFAS (perfluoroalkyl compounds) has been continuously increasing. In addition to single compounds, researchers are increasingly focusing on "total PFAS" analysis to more comprehensively assess environmental risks. At present, the commonly used analytical methods for total PFAS include combustion ion chromatography (CIC) and particle excited gamma ray (PIGE), but the operation is more complex, and researchers need a simpler and more efficient solution.
The method of using ICP-MS/MS to detect fluoride content is gradually maturing, which can be used for convenient quantitative analysis of total fluoride (TF) and extractable organic fluoride (EOF) fluoride content in food and environment. However, the existing method for determining total fluoride using Agilent 8800/8900 ICP-MS/MS requires the use of an s lens group or a combination of a 1.5 mm inner diameter torch tube and an x lens group, rather than just using the conventional combination of a 2.5 mm inner diameter torch tube and an x lens group. In order to meet the needs of more environmental and food analysis laboratories, this article will introduce optimized instrument analysis methods.
Introduction to the principle of ICP-MS/MS determination of total fluoride
The core principle of ICP-MS/MS total fluoride quantification is as follows: using high-temperature plasma to break the C-F bond in organic fluorides, allowing fluoride ions to combine with barium ions added online to form characteristic ion clusters[138Ba19F]+And achieve quantification by detecting the ion cluster. However, interference ion clusters are usually generated during detection. To solve this problem, NH can be used3/He reaction gas transfers the mass of the target ion cluster to a higher m/z, effectively distinguishing interference; You can also use O2/H2Mixing reaction gases to prioritize the reaction of interfering ions and preserve the target signal.
Figure 1 (1) ICP-MS/MS in mass transfer mode, using NH3/As the gas in the reaction pool, He[138Ba19F]+(m/z = 157) 形成 [138Ba19F(NH3)3]+(m/z=208) ion clusters are used to determine the concentration of F ions; (2) ICP-MS/MS in in-situ mass mode, using O2And H2The mixed gas is used as the reaction pool gas to react various interfering ion clusters (m/z=157) to obtain ion clusters with other mass numbers, and then the retained ions are measured[138Ba19F]+Ionic clusters (m/z=157) were used to obtain quantitative results of F ion concentration.
Comparison of Instrument Settings
Focusing on Setting 2 and Setting 3 in the parameter settings of the testing method shown in Table 1, it aims to ensure that a 1:1 methanol pure water solution (50% MeOH) can be used with a 2.5 mm inner diameter torch tube without the use of optional gases (Ar/O)2Stable operation under mixed gas conditions. It should be noted that due to the use of 50% MeOH as the standard curve solution and solvent for the sample, the 2.5mm inner diameter torch tube is not suitable for peristaltic pump speeds greater than 0.1 rps. Therefore, it takes a long time to introduce and clean between samples.
Table 1 Comparison of Three Typical Instrument Parameters for Fluorine Analysis by Agilent 8900 ICP-MS/MS
parameter |
unit |
Setting 1 |
Setting 2 |
Set 3 |
Inner diameter of torch tube |
mm |
1.5 |
2.5 |
2.5 |
RF power |
W |
1300 |
1250 |
1250 |
sampling depth |
mm |
8 |
10 |
10 |
Atomizing gas |
L/min |
0.70 |
1.10 |
1.00 |
peristaltic pump |
rps |
0.1 |
0.1 |
0.1 |
Atomization chamber temperature |
°C |
–3 |
–3 |
–3 |
Compensation gas |
L/min |
0.48 |
0.46 |
0.39 |
Extract lens 1 |
V |
–15 |
–15 |
–15 |
Extract lens 2 |
V |
–135 |
–135 |
–149 |
Helium flow rate |
mL/min |
1 |
1 |
0 |
hydrogen flow rate |
mL/min |
0 |
0 |
3 |
The third gas flow rate (NH)3/He) |
% |
75 |
53 |
0 |
The fourth gas flow rate (O2) |
% |
0 |
0 |
50 |
Eight pole deflection voltage |
V |
–6 |
–9 |
–10 |
Axis acceleration |
V |
0.2 |
0.2 |
1 |
Energy discrimination |
V |
–15 |
–17 |
–20 |
Experimental results: The detection limit of ICP-MS/MS method meets the requirements of conventional total fluoride detection
According to Table 2, although there are still differences in signal sensitivity among the three testing methods, there is no significant difference in instrument detection limits, and all of them can meet the requirements of conventional total fluoride detection.
Table 2 Typical signal sensitivity and instrument detection limit obtained under three different instrument settings
parameter |
unit |
Setting 1 |
Setting 2 |
Set 3 |
Signal sensitivity |
cps/μg/g |
1300 |
2490 |
16700 |
Instrument detection limit |
μg/g |
0.008 |
0.006 |
0.005 |
Experimental results: ICP-MS/MS method has excellent precision
To verify the accuracy and precision of the three instrument setup schemes, it is necessary to prepare PFOA and PFOS standard solutions with known fluoride concentrations and perform quantitative analysis on them separately (see Table 3 for the results). From the table, it can be seen that the recovery rate of F measured under three instrument settings is between 97% and 103%, and the relative standard deviation (RSD) of each sample's three quantitative analysis results is less than 5%, indicating that all three instrument settings can meet the requirements for accurately determining the total fluoride content in organic fluorides.
Table 3 Analysis results of total F in two PFAS standard solutions measured under three different instrument settings
Type of compound |
Preparation concentration of F in PFAS standard solution |
Instrument method setting |
Actual measured average concentration |
RSD of measured average concentration (n=3) |
recovery rate |
μg/g |
μg/g |
% |
% |
||
PFOA |
0.220 |
Setting 1 |
0.226 |
2.4 |
102.9 |
Setting 2 |
0.226 |
4.1 |
102.7 |
||
Set 3 |
0.215 |
1.9 |
97.6 |
||
PFOS |
0.547 |
Setting 1 |
0.552 |
0.2 |
100.9 |
Setting 2 |
0.546 |
0.7 |
99.8 |
||
Set 3 |
0.535 |
0.9 |
97.7 |
Conclusion
This experiment used Agilent 8900 ICP-MS/MS (x lens+2.5 mm torch tube) to determine the total fluoride in organic fluorides. The method is sensitive, accurate, and precise, and all three parameter settings can stably achieve quantitative analysis, combining flexibility and practicality, providing practical technical support and convenient advantages for scientific research and daily monitoring.
More technical details and parameters,
Please click on the image below to learn more,
Get detailed application content!
