CN106568867A

CN106568867A - Quantitative method of chain-like methylsiloxane in PDMS

Info

Publication number: CN106568867A
Application number: CN201610994138.7A
Authority: CN
Inventors: 冯精兰; 张飞; 赵佳慧; 苏现伐; 孙剑辉
Original assignee: Henan Normal University
Current assignee: Henan Normal University
Priority date: 2016-10-31
Filing date: 2016-10-31
Publication date: 2017-04-19
Anticipated expiration: 2036-10-31
Also published as: CN106568867B

Abstract

The invention discloses a quantitative method of chain-like methylsiloxane in PDMS, and belongs to the technical field of analytical chemistry. According to the quantitative method, the peak area of chain-like methylsiloxane in PDMS under GC-FID response is converted into peak area of M4Q with the same mass concentration under GC-FID response, and is converted into the content of chain-like methylsiloxane in PDMS quantified with a M4Q standard curve, an adopted specific formula is disclosed in the invention, wherein Ai is used for representing the peak area of one chain-like methylsiloxane under GC-FID response, ci is used for representing the mass concentration of chain-like methylsiloxane corresponding to peak area Ai, k is used for representing a monomial coefficient of a linear relation mathematical expression formula of the M4Q standard curve, and b is used for representing the algebraic value of a constant term of the M4Q standard curve. Compared with the prior art, the quantitative method possesses following beneficial effect: measuring process is simple; and both measuring accuracy and precision are relatively high.

Description

The quantitative approach of chain methylsiloxane in PDMS

Technical field

The invention belongs to technical field of analytical chemistry, and in particular to the quantitative square of chain methylsiloxane in a kind of PDMS Method.

Background technology

Polymethyl siloxane (siloxane) is a class with the Si-O keys that repeat as major key, and methyl is directly connected on silicon atom Chain or cyclic polymer, its general structure is：

[R_nSiO_4-n/2]_m

R in formula be organic group, such as Me, n be silicon atom connect organic group number (1-3), m be the degree of polymerization (m >= 2).Polymethyl siloxane includes chain (L) methylsiloxane (dimethyl silicone polymer, PDMS) and ring-type (D) from textural classification Methylsiloxane (ring dimethyl siloxane).Polymethyl siloxane because its excellent performance be widely used in it is electric, building, The industries such as automobile, light industry, cosmetics, medical treatment and food, in its substantial amounts of application process, polymethyl siloxane is moved through various Shifting approach, enters in a large number among environment and forms persistence presence.Existing toxicologic study shows polymethyl siloxane to animal Neural, immune and reproductive system produce toxic action, with carcinogenic and teratogenesis.In view of polymethyl siloxane usage amount is huge Big and have wide range of applications, the environmental problem of polymethyl siloxane has become study hotspot.And among actual research, when grinding When studying carefully impact of the dimethyl silicone polymer (PDMS) to environment, it is to the qualitative and quantitative analysis of dimethyl silicone polymer (PDMS) Requisite part, for cyclic methyl siloxane and part chain methylsiloxane (silicon atom number≤5), due to its list Mark is readily available, therefore their dosing process is simple and accurate, but for silicon atom number>5 chain methylsiloxane, it is single Mark is difficult to obtain, with PDMSQualitative and quantitative analysis is carried out as standard specimen, therefore for PDMSMiddle chain first Radical siloxane it is accurate, simply quantitative, just seem extremely important and necessity.Existing GC-FID is to PDMSMiddle chain The quantitative approach of methylsiloxane has three kinds：One is area normalization method, and two is internal standard method, and three is that external standard method (has used a certain kind The calibration curve for having single target methylsiloxane approximately removes quantitative PDMSThe content of middle chain methylsiloxane).These three The defect that quantitative approach is present is the methylsiloxane for not accounting for different molecular weight and different structure, the sound in GC-FID Should be this important factor having differences, therefore the quantitative approach that these differences are taken into account, it is to PDMSIn The premise of the content accurate quantification of chain methylsiloxane.Hydrogen ion flame detector (FID) is mass flow rate sensitive detector, to hydrocarbonylation The response theory of thing, is to their contained organic carbon ionization in hydrogen flameProcess.And In PDMS, Si-C bond energys (57.6kJ/mol) are approximately 1/2nd of Si-O keys (101kJ/mol), and than the key of C-C key Energy (84.9kJ/mol) is also low, so the more easy fracture of the organic carbon in methylsiloxane among hydrogen ion flame, carries out electricity Ionization, produces signal, and the experiment of reality is also demonstrated that, methylsiloxane can be to be detected by GC-FID.From GC-FID pair The principle of detectable substance response is set out, and for the defect existing for chain methylsiloxane quantitative approach in current PDMS, sets up new Quantitative approach to solve the problems, such as three aspect：(1) to PDMSIn contained chain methylsiloxane species it is qualitative；(2) Gas chromatographic flame ionization detector (GC-FID) carbon response theory is adapted to the checking of methylsiloxane detection；(3) quantitative number Learn the foundation of model.

The content of the invention

Present invention solves the technical problem that there is provided, a kind of method is simple and accuracy of measurement and precision are higher The quantitative approach of chain methylsiloxane in PDMS.

The present invention is to solve above-mentioned technical problem to adopt the following technical scheme that, the quantitative square of chain methylsiloxane in PDMS Method, it is characterised in that concretely comprise the following steps：

The carbon containing mass ratio of the carbon containing quality of unit mass M4Q and a certain chain methylsiloxane of unit mass is equal to single Peak area of position peak area and unit mass a certain chain methylsiloxane of mass M 4Q in GC-FID in GC-FID it Than concrete formula is expressed as：

In formula：For the carbon containing quality of unit mass M 4Q,For containing for a certain chain methylsiloxane of unit quality Carbonaceous amount, A_M4QFor the peak area of unit mass M 4Q, A_iFor the peak area of a certain chain methylsiloxane of unit quality；

Because the carbon containing quality of M4Q and a certain chain methylsiloxane is determined by phosphorus content percentage, To equation below：

In formula：m_M4QFor the unit mass of M4Q, m_iFor the unit mass of a certain chain methylsiloxane,Containing for M4Q Carbon amounts percentage,For the phosphorus content percentage of a certain chain methylsiloxane；

Merge formula (1) and (2) and obtain equation below：

When the molecular formula of a certain chain methylsiloxane determinesAs definite value,Also it is definite value, now For definite value, for the ease of calculate and express byIt is expressed asShouldFor nondimensional constant, thus can obtain；

By formula (4) by the peak area A of the arbitrary chain methylsiloxane in PDMS_iIt is converted into corresponding inferior quality concentration M4Q peak area A_M4Q, be so converted to the calibration curve of M4Q come the content of chain methylsiloxane in quantitative PDMS, tool Body formula is：

In formula：A_iFor the peak area that a certain chain methylsiloxane is responded in GC-FID, c_iFor peak area A_iUnder correspondence The mass concentration of chain methylsiloxane, k is the Monomial coefficient for obtaining M4Q calibration curves, and b is to obtain M4Q calibration curves The algebraic value (intercept of linear relationship mathematic(al) representation) of constant term.

The present invention has the advantages that compared with prior art：Measurement process is simple, the degree of accuracy of measurement and accurate Degree is higher.

Specific embodiment

The above of the present invention is described in further details by the following examples, but this should not be interpreted as this The scope for inventing above-mentioned theme is only limitted to below example, and all technologies realized based on the above of the present invention belong to this Bright scope.

The qualitative analysis of embodiment 1

PDMSGC-MS analysis conditions：HP-5MS chromatographic columns (30m × 0.25mm × 0.25 μm), temperature programming：5min is kept, Splitless injecting-Sample, carrier gas is helium, and sample size is 1 μL。

Ion gun is electron bombardment ionization source (EI), and the pattern for adopting is Scan patterns；Data Collection ＆ Processing System is HPization Learn work station.

The PDMS of 10mg/LStandard specimen is analyzed with GC-MS, and its result is to detect 12 advantage peaks, qualitative results For chain methylsiloxane, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14, L15, L16 respectively are, wherein also There is a kind of cyclic methyl siloxane D7, its peak is between L6 and L7.(note：" L " represents chain, and D represents ring-type, and numeral represents chain Silicon atom number in shape methylsiloxane, following presentation is ibid).

Theoretical validations of the GC-FID of embodiment 2 to PDMS response theories

The GC-FID analysis conditions of eight kinds of single marks (D3-D6, L3-L5 and M4Q)：HP-5MS chromatographic columns (30m × 0.25mm × 0.25 μm), temperature programming：5min, Splitless injecting-Sample is kept to carry Gas is helium, and sample size is 1 μ L.

By four kinds of cyclic methyl siloxanes list mark (D3, D4, D5, D6), three kinds of chain methylsiloxane list marks (L3, L4, L5) and M4Q be configured to the other mixed mark of 7 concentration levels (0.5mg/L, 1mg/L, 5mg/L, 10mg/L, 20mg/L, 50mg/L, 100mg/L), peak areas of the different PDMS under different quality concentration is obtained.Because sampling volume is 1 μ L, so can obtain The corresponding peak area of siloxanes under different quality.Again because for the methylsiloxane for determining, its percent carbon content The value being to determine, it is possible to make the relation of eight kinds of single mark methylsiloxane carbonaceous amounts and its peak area, the result of experiment is The quality of the carbon of methyl oxygen alkane and its peak area in GC-FID are linear, coefficient Rs²0.999 with On.Additionally, experiment obtains the corresponding peak area of quality of the unit carbon of the methylsiloxane of eight kinds of different structures and molecular weight： 13.43170PA/ng(D3)、13.90083PA/ng(D4)、12.75261PA/ng(D5)、12.52741PA/ng(D6)、 12.12.61684PA/ng (L3), 13.10146PA/ng (L4), 12.61684PA/ng (L5) and 10.95583PA/ng (M4Q), This explanation GC-FID carbon response theory can be used for response of the methylsiloxane in GC-FID, and different molecular weight and molecule Response of the methylsiloxane of structure in GC-FID has differences.

The foundation of the quantitative model of embodiment 3

In formula：m_M4QFor the unit mass of M4Q, m_iFor the unit mass of a certain chain methylsiloxane,For M4Q's Phosphorus content percentage,For the phosphorus content percentage of a certain chain methylsiloxane；

Note：

Merge formula (1) and (2) and obtain equation below：

By formula (4) by the peak area A of the arbitrary chain methylsiloxane in PDMS_iIt is converted into corresponding inferior quality concentration M4Q peak area A_M4Q, so it is converted to the calibration curve of M4Q come the content of chain methylsiloxane in quantitative PDMS.

Therefore, according to M4Q calibration curve (y=4.27586x-0.3919, the R for obtaining under experimental conditions²= 0.9996) it is, and available with reference to formula (4)：

In formula：A_iFor the peak area that certain mass concentration, a certain chain methylsiloxane are responded in GC-FID, c_iFor peak Area A_iThe mass concentration of the chain methylsiloxane under correspondence.

Due to the calibration curve y=kx-b of M4Q, (y represents peak area；X represents mass concentration；K represents Monomial coefficient；b For the algebraic value (i.e. the intercept of linear relationship mathematic(al) representation) of constant term) affected by conditions such as instruments, in different model Can change under GC-FID instruments, therefore, final PDMSIn the quantitative model of arbitrary chain methylsiloxane can table It is shown as：

In formula：A_iFor the peak area that certain mass concentration, a certain chain methylsiloxane are responded in GC-FID, c_iFor peak Area A_iThe mass concentration of the chain methylsiloxane under correspondence, k represents the linear relationship mathematic(al) representation of the calibration curve of M4Q Monomial coefficient；B is the algebraic value (i.e. intercept) of the constant term of the linear relationship mathematic(al) representation of the calibration curve of M4Q.

Embodiment 4 is to PDMSIn chain methylsiloxane carry out quantitatively

Quantitative result is as follows：

Contrast actual verification result, the newly-built quantitative approach to chain methylsiloxane in PDMS obviously than other three Plant quantitative approach more accurate.

General principle, principal character and the advantage of the present invention is embodiment above describes, the technical staff of the industry should Understand, the present invention is not restricted to the described embodiments, the original for simply illustrating the present invention described in above-described embodiment and specification Reason, under the scope without departing from the principle of the invention, the present invention also has various changes and modifications, and these changes and improvements each fall within In the scope of protection of the invention.

Claims

The quantitative approach of chain methylsiloxane in 1.PDMS, it is characterised in that concretely comprise the following steps：

The carbon containing mass ratio of the carbon containing quality of unit mass M4Q and a certain chain methylsiloxane of unit mass is equal to unit matter The ratio of peak area of peak area and unit mass a certain chain methylsiloxanes of the amount M4Q in GC-FID in GC-FID, tool Body formula is expressed as：

$\frac{m_{M 4 Q}^{C}}{m_{i}^{C}} = \frac{A_{M 4 Q}}{A_{i}} - - - (1)$

In formula：For the carbon containing quality of unit mass M 4Q,It is a certain chain methylsiloxane of unit quality containing carbonaceous Amount, A_M4QFor the peak area of unit mass M 4Q, A_iFor the peak area of a certain chain methylsiloxane of unit quality；

Because the carbon containing quality of M4Q and a certain chain methylsiloxane is determined by phosphorus content percentage, obtain as Lower formula：

$\frac{m_{M 4 Q} \cdot C_{M 4 Q}^{P e r}}{m_{i} \cdot C_{i}^{P e r}} = \frac{m_{M 4 Q}^{C}}{m_{i}^{C}} - - - (2)$

In formula：m_M4QFor the unit mass of M4Q, m_iFor the unit mass of a certain chain methylsiloxane,For the phosphorus content of M4Q Percentage,For the phosphorus content percentage of a certain chain methylsiloxane；

Merge formula (1) and (2) and obtain equation below：

$\frac{A_{M 4 Q}}{A_{i}} = \frac{C_{M 4 Q}^{P e r}}{C_{i}^{P e r}} - - - (3)$

When the molecular formula of a certain chain methylsiloxane determinesAs definite value,Also it is definite value, nowIt is fixed Value, for the ease of calculate and express byIt is expressed asShouldFor nondimensional constant, thus can obtain；

$A_{M 4 Q} = A_{i} \cdot C_{R}^{P e r} - - - (4)$

By formula (4) by the peak area A of the arbitrary chain methylsiloxane in PDMS_iIt is converted into the M4Q of corresponding inferior quality concentration Peak area A_M4Q, be so converted to the calibration curve of M4Q come the content of chain methylsiloxane in quantitative PDMS, it is concrete public Formula is：

$c_{i} = \frac{A_{i} \cdot C_{R}^{P e r} + b}{k} - - - (5)$

In formula：A_iFor the peak area of a certain chain methylsiloxane of unit quality, c_iFor peak area A_iChain methyl silicon under correspondence The mass concentration of oxygen alkane, k is the Monomial coefficient for obtaining M4Q calibration curves, and b is the generation of the constant term for obtaining M4Q calibration curves Numerical value.