Raman spectrum detection method for unsaturated components of old-pit emerald wax petroleum

Abstract

The invention relates to a Raman spectrum detection method for unsaturated components of wax petroleum of old-pit jadeite, and aims to solve the problem that old-pit jadeite is wrongly classified due to the fact that natural wax petroleum is misjudged to be resin adhesive by an infrared spectrum in traditional commodity inspection. Characteristic peak combinations are identified through a microscopic Raman technology: fat chain vibration peaks (2929 + / -10, 2881 + / -10, 2847 + / -10), crystal double peaks (1463 + / -10 / 1440 + / -10), trace unsaturated component weak peaks (3035 + / -10 / 3065 + / -10, strength lt; the method comprises the following steps of: establishing a clear distinguishing standard with resin adhesive (1111 + / -5 and 1609 + / -5 peaks) by combining the characteristic peaks (1350 + / -10D peak and 1600 + / -10G peak) and carbonization characteristic peaks (1350 + / -10D peak and 1600 + / -10G peak) of wax petroleum in combination with star-like capillary pore distribution and ice crack linear filling structure verification of the wax petroleum. According to the method, the detection accuracy of the natural organic matters in the old-pit jadeite reaches 98% or above, the revision of an organic matter criterion in the GB / T16553-2017 standard is promoted, and the industry difficulty that ten millions of historical jadeite collections cannot be legally circulated due to false detection is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of jadeite identification, in particular to a Raman spectrum detection method for unsaturated components of waxy petroleum in Laogeng jadeite. BACKGROUND

[0002] Traditional jadeite identification technology relies on infrared spectrum detection of organic matter, and according to the standard GB / T16553-2017, the peaks of 3035 and 3065 wave numbers are determined as the characteristics of resin glue, resulting in that Laogeng seed material jadeite containing natural waxy petroleum is systematically misjudged as "bleached and filled treatment goods". Research shows that infrared spectrum cannot distinguish the chemical differences between natural waxy petroleum and artificial resin glue, and lacks sensitivity to trace unsaturated components (<10%). -1 Although existing Raman technology can detect organic matter, international detection agencies mistakenly attribute the weak peak of 1600±10 to resin glue or ignore the carbonization peak of 1350-1600 cm

[0003] This technical defect directly leads to the misclassification of Laogeng jadeite, hinders the market circulation of cultural heritage level jadeite, and urgently needs to establish a precise identification system for natural organic matter based on Raman spectrum. SUMMARY

[0004] In order to solve the problems of the prior art, the present application provides a Raman spectrum detection method for unsaturated components of waxy petroleum in Laogeng jadeite.

[0005] In order to solve the above technical problems, the present application is realized by the following technical scheme: in the first aspect, the Raman spectrum detection method for unsaturated components of waxy petroleum in Laogeng jadeite comprises the following steps:

[0006] S1: preparing a Laogeng seed material jadeite sample after polishing and cleaning;

[0007] S2: positioning the solid organic matter in the sample under 500-1000 times magnification using a microscopic laser Raman spectrometer;

[0008] S3: obtaining Raman spectrum data of the micro area positioning;

[0009] S4: identifying the following characteristic peak combinations:

[0010] S41: representing the 2929±10, 2881±10, 2847±10, 2725±10, 1463±10, 1440±10, 1295±10, 1169±10, 1132±10, 1061±10 wave number peak system of long-chain waxy petroleum;

[0011] S42: representing the weak peaks (intensity <10% reference peak) of 3035±10 and / or 3065±10 of trace unsaturated components.

[0012] S43: Optionally present 1350 ± 10 (D peak) and 1600 ± 10 (G peak) carbonization characteristic peaks;

[0013] S5: Determine the presence of natural solid waxy petroleum containing unsaturated components in the sample by characteristic peak combination.

[0014] In one embodiment of the first aspect, the unsaturated component concentration is less than 10%, and the determination is based on:

[0015] 3035 ± 10 and 3065 ± 10 peak intensity ratio is not more than 10% of the main peak (2929 ± 10);

[0016] When the 1600 ± 10 peak is present, its half-height width is > 15 cm -1 To distinguish from the sharp peaks of resin glue.

[0017] In one embodiment of the first aspect, the identification criteria for long-chain waxy petroleum are the simultaneous presence of:

[0018] Fatty chain characteristic peak group: 2929 ± 10, 2881 ± 10, 2847 ± 10;

[0019] Crystallization region characteristic peak: 1463 ± 10 and 1440 ± 10 doublet;

[0020] Methine wagging vibration peak: 1295 ± 10;

[0021] Carbon chain skeleton vibration peak group: 1169 ± 10, 1132 ± 10, 1061 ± 10.

[0022] In one embodiment of the first aspect, the micro-laser Raman test conditions include:

[0023] Laser wavelength 532 nm or 785 nm;

[0024] Power 0.5-5 mW;

[0025] Integration time 10-60 seconds;

[0026] Spectral resolution ≤ 3 cm -1 .

[0027] In one embodiment of the first aspect, further comprising the determination criteria for excluding the interference of resin glue:

[0028] Missing 1111 ± 5, 1185 ± 5, 1609 ± 5 epoxy resin characteristic peaks;

[0029] 3035 / 3065 peak intensity ratio is more than 90% lower than the resin glue standard sample;

[0030] absence of 1700-1800 cm -1 carbonyl characteristic peak.

[0031] In a second aspect, a method for identifying old pit seed jadeite raw stone, using Raman spectroscopy to detect the unsaturated components of old pit jade wax oil to confirm:

[0032] naturally occurring solid wax oil;

[0033] The wax oil contains 0.1-10% unsaturated components;

[0034] Excluding artificial resin glue filling treatment.

[0035] In a specific embodiment of the second aspect, it further comprises verifying the natural property by the following distribution characteristics:

[0036] The organic matter is dispersed in the mineral capillary pores in the form of star points;

[0037] Linearly distributed in sodium aluminum pyroxene grain boundary ice cracks;

[0038] The network filling structure unique to the glue treatment.

[0039] In a third aspect, a method for revising the detection standard of jadeite, the detection result of which is reclassified as:

[0040] A-grade jadeite containing natural organic matter;

[0041] B / C-grade jadeite distinguished from glue treatment.

[0042] In a specific embodiment of the third aspect, it specifically comprises:

[0043] Amend the organic matter=treatment determination clause in GB / T16553-2017;

[0044] Establish a database of wax oil characteristic peaks;

[0045] Develop unsaturated component concentration threshold standards.

[0046] In a fourth aspect, a new use of Raman spectroscopy detection equipment in jadeite identification:

[0047] Used to identify the 2929±10, 2881±10, 2847±10 characteristic peak system of natural wax oil;

[0048] Used to distinguish natural unsaturated components from artificial resin glue 3035±10 / 3065±10 weak peaks;

[0049] Used to detect carbonization-derived 1350±10 (D peak) and 1600±10 (G peak) double peaks.

[0050] The beneficial effects of the present application are:

[0051] 1. Through the accurate identification of the combination of Raman spectral characteristic peaks (2929±10, 2881±10, 2847±10 fat chain vibration peaks, 1463±10 / 1440±10 crystallization double peaks, and 3035±10 / 3065±10 weak peaks), the chemical nature of natural waxy petroleum in Laogeng seed jade and the occurrence state (concentration 0.1-10%) of trace unsaturated components thereof are first revealed. Compared with the defect of misjudging resin glue by relying only on the 3035 / 3065 peaks in infrared spectroscopy, the present method introduces the half-height width index (>15 cm -1 ) of the carbonization derived D peak (1350±10) and G peak (1600±10) and the microscopic distribution characteristics (star-shaped capillary pore filling and linear distribution of grain boundary ice cracks), and establishes a clear distinction standard for natural waxy petroleum and artificial resin glue (1111±5, 1185±5, 1609±5 sharp peaks), which completely solves the technical problem of Laogeng jade being misjudged as B / C goods due to the inclusion of natural organic matter;

[0052] 2. The present technology directly promotes the scientific revision of jade identification standards, and through the establishment of a waxy petroleum characteristic peak database and the quantification of the concentration threshold of unsaturated components,

[0053] provides a technical basis for the update of the organic matter criterion in GB / T16553-2017 and other standards. This enables millions of historical Laogeng seed jade to get rid of the stigma of “treatment goods” and restore its natural A-grade identity, which is expected to drive the revaluation of the trillion-level historical inventory of jade. At the same time, the non-destructive detection based on microscopic Raman ensures the safety of the identification of cultural relics-grade jade, and provides core technical support for the standardized development of cultural heritage protection and high-end jade trading market. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a schematic diagram of the laser Raman spectrum of the paraffin wax of the present application.

[0055] Figure 2 is a schematic diagram of the laser Raman spectrum of the epoxy resin of the present application.

[0056] Figure 3 is a schematic diagram of the laser Raman spectrum of the jadeite, a constituent mineral of jade, of the present application.

[0057] Figure 4 is a schematic diagram showing the Laogeng seed jade of the present application under 500 times magnification.

[0058] Figure 5 is a schematic diagram of the laser Raman spectrum of the solid organic matter in the Laogeng seed jade of the present application.

[0059] Figure 6 is a schematic diagram of the Lao'keng seed material jadeite shown under 500 times magnification.

[0060] Figure 7 is a schematic diagram of the laser Raman spectrum of the solid organic matter in the Lao'keng seed material jadeite.

[0061] Figure 8 is a schematic diagram of the Lao'keng seed material jadeite shown under 500 times magnification.

[0062] Figure 9 is a schematic diagram of the laser Raman spectrum of the solid organic matter in the Lao'keng seed material jadeite.

[0063] Figure 10 is a schematic diagram of the Lao'keng seed material jadeite shown under 500 times magnification.

[0064] Figure 11 is a schematic diagram of the laser Raman spectrum of the solid organic matter in the Lao'keng seed material jadeite.

[0065] Figure 12 is a schematic diagram of the Lao'keng seed material jadeite shown under 1000 times magnification.

[0066] Figure 13 is a schematic diagram of the laser Raman spectrum of the solid organic matter in the Lao'keng seed material jadeite.

[0067] Figure 14 is a schematic diagram of the Lao'keng seed material jadeite shown under 1000 times magnification.

[0068] Figure 15 is a schematic diagram of the laser Raman spectrum of the solid organic matter in the Lao'keng seed material jadeite. DETAILED DESCRIPTION

[0069] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0070] The Lao'keng jadeite wax petroleum unsaturated component Raman spectrum detection method shown in Figures 1 to 15 1) Lao'keng seed material raw stone sample, need to polish the light surface, clean with distilled water or alcohol;

[0071]

[0072] ​2) The experiment is carried out by using Horiba Xplora confocal microscopic laser Raman spectrometer equipped with microscopic amplification and micro-area fixed-point analysis function;

[0073] 3) The solid-state organic matter in the fixed-point sample under 500 times or 100 times amplification is scanned by using laser, and the Raman spectrum of the micro-area fixed-point solid-state organic matter is obtained;

[0074] 4) According to the combination of 2929, 2881, 2847, 2725, 1463, 1440, 1295, 1169, 1132, 1061 wave numbers on the Raman spectrum, the solid-state organic matter is accurately determined to be solid-state long-chain waxy petroleum;

[0075] 5) According to the appearance of 3035±10, 3065±10 weak peaks alone or in combination on the Raman spectrum, the existence of unsaturated hydrocarbon components in the solid-state long-chain waxy petroleum in the old pit jade can be accurately determined, and the component concentration is very low

usually less than 10%

[0076] Figure 1 The laser Raman spectrum of paraffin wax shows the characteristic absorption peak combination of 1061, 1132, 1169, 1295, 1440, 1463, 2725, 2847, 2881, 2929 wave numbers, according to which the existence of solid-state long-chain waxy petroleum can be determined.

[0077] Figure 2 The laser Raman spectrum of epoxy resin, in which the four Raman strong peak bands of 1111 cm-1, 1185 cm-1, 1609 cm-1, 3067 cm-1 are the Raman bands specific to epoxy resin and different from white wax.

[0078] Figure 3 The laser Raman spectrum of jadeite, a constituent mineral of jade, shows that all Raman peaks are in the low frequency region, including 204, 374, 575, 700, 990, 1041 wave numbers.

[0079] Figure 4The seed material of Laogeng jade shows that the solid organic matter exists in the capillary pores caused by the interlaced arrangement of the constituent mineral jadeite, and is dispersed in star point shape, and is distributed in linear shape on the crystal grain boundaries between the jadeite crystal particles. The linear distribution is the ice cracks caused by the stress release and strain recovery of the seed material of Laogeng jade in the supergene environment due to the release of the surrounding pressure accumulated in the previous formation period, and the appropriate relaxation of the close contact between the crystal particles, and the infiltration and evolution of water molecules and bacteria microorganisms with water.

[0080] Figure 5 The laser Raman spectrum of the solid organic matter in the seed material of Laogeng jade shows the characteristic absorption peak combination of 1135, 1295, 1441, 1459, (1599), 2725, 2851, 2883, 2929 wave numbers, and according to the peak combination, it can be determined that there is solid long-chain waxy petroleum; but particularly, a weak peak appears at 3010 wave numbers

the standard position is at 3035 wave numbers, showing a certain degree of drift

[0081] Figure 6 The seed material of Laogeng jade shows that the solid organic matter exists in the capillary pores caused by the interlaced arrangement of the constituent mineral jadeite, and is dispersed in star point shape, and is distributed in linear shape on the crystal grain boundaries between the jadeite crystal particles. The linear distribution is the ice cracks caused by the stress release and strain recovery of the seed material of Laogeng jade in the supergene environment due to the release of the surrounding pressure accumulated in the previous formation period, and the appropriate relaxation of the close contact between the crystal particles, and the infiltration and evolution of water molecules and bacteria microorganisms with water.

[0082] Figure 7 The laser Raman spectrum of the solid organic matter in the seed material of Laogeng jade shows the characteristic absorption peak combination of 1061, 1132, 1169, 1295, (1338), 1441, 1460, (1594), 2963 wave numbers, and according to the peak combination, it can be determined that there is solid long-chain waxy petroleum; but particularly, a weak peak appears at 3065 wave numbers

the standard position is at 3065 wave numbers

[0083] Figure 8The seed material of Laogeng jade shows that the solid organic matter exists in the capillary pores caused by the interlaced arrangement of the constituent mineral jadeite, and is dispersed in star point shape, and is distributed in linear shape on the crystal grain boundaries between the jadeite crystal particles. The linear distribution is the ice cracks caused by the stress release and strain recovery of the seed material of Laogeng jade in the supergene environment due to the removal of the surrounding pressure accumulated in the previous formation period, and the appropriate relaxation of the close contact between the crystal particles, and the infiltration and evolution of water molecules and bacteria microorganisms with water.

[0084] Figure 9 The laser Raman spectrum of the solid organic matter in the Laogeng jade shows the characteristic absorption peak combination of 1463, (1604, G peak), 2869, 2907, 2936 wave numbers, and according to the peak combination, it can be determined that there is solid long-chain waxy petroleum; but especially, a weak peak appears at 3068 wave numbers

the standard position is at 3065 wave numbers

this weak peak does not often appear

[0085] Figure 10 The seed material of Laogeng jade shows that the solid organic matter exists in the capillary pores caused by the interlaced arrangement of the constituent mineral jadeite, and is dispersed in star point shape, and is distributed in linear shape on the crystal grain boundaries between the jadeite crystal particles. The linear distribution is the ice cracks caused by the stress release and strain recovery of the seed material of Laogeng jade in the supergene environment due to the removal of the surrounding pressure accumulated in the previous formation period, and the appropriate relaxation of the close contact between the crystal particles, and the infiltration and evolution of water molecules and bacteria microorganisms with water.

[0086] Figure 11 The laser Raman spectrum of the solid organic matter in the Laogeng jade shows the characteristic absorption peak combination of (1338, D peak), 1463, (1606, G peak), 2881, 2922, 2970 wave numbers, and according to the peak combination, it can be determined that there is solid long-chain waxy petroleum; but especially, a weak peak appears at 3066 wave numbers

the standard position is at 3065 wave numbers

this weak peak does not often appear

[0087] 6) The 1350±10 cm -1 appears in the Raman spectrum. -1 Weak peak combination, not the characteristic peak of biological wax oil or resin glue. Among them, the 1600±10 cm -1 peak is due to the benzene ring vibration peak (~1608 cm -1) position close, once been part of the preliminary classification of organic glue residue; and 1350±10cm -1 The peak may not be detected in some experiments due to low intensity or instrument sensitivity limitations. This study believes that the peak combination is derived from the thermal induction carbonization reaction of trace unsaturated hydrocarbons (<10%) in Laogeng jade solid wax oil under laser irradiation, forming D peak (1350±10cm - 1) G peak (1600±10cm -1 ) representing graphitized ordered structure.

[0088] Figure 12 Laogeng seed jade shows star point-like dispersion of solid organic matter in capillary pores caused by interlaced arrangement of constituent minerals sodalite, and linear distribution on the grain boundaries between sodalite crystal particles. This linear distribution is the ice crack caused by the release of stress accumulated during the formation period and the strain recovery due to the release of confining pressure in the supergene environment. The tight contact between crystal particles is properly relaxed, and water molecules and bacteria and microorganisms entering with water have penetrated and evolved.

[0089] Figure 13 The laser Raman spectrum of solid organic matter in Laogeng seed jade shows characteristic absorption peak combination at 1143, (1341, D peak), 1461, (1601, G peak), 2854, 2884, 2937 wave numbers. According to this peak combination, it can be determined that there is solid long-chain wax oil; but especially at 1341 wave number

D peak, standard position at 1350±10 wave number, but this weak peak does not always appear

this weak peak often appears

[0090] Figure 14 Laogeng seed jade shows star point-like dispersion of solid organic matter in capillary pores caused by interlaced arrangement of constituent minerals sodalite, and linear distribution on the grain boundaries between sodalite crystal particles. This linear distribution is the ice crack caused by the release of stress accumulated during the formation period and the strain recovery due to the release of confining pressure in the supergene environment. The tight contact between crystal particles is properly relaxed, and water molecules and bacteria and microorganisms entering with water have penetrated and evolved.

[0091] Figure 15The laser Raman spectrum of the solid organic matter in the old pit seed jade raw stone shows the characteristic absorption peak combination of 1135, 1295, 1441, 1463, (1596, G peak), 2727, 2851, 2883, 2930 wave numbers, and according to the peak combination, it can be determined that there is solid long-chain waxy petroleum; but particularly, a weak peak appears at 1596 wave number (G peak, the standard position is at 1600±10 wave number), which is not the characterization of unsaturated hydrocarbons of resin, but the existence of trace (<10%) unsaturated hydrocarbon components in the solid long-chain waxy petroleum of the old pit seed jade raw stone.

[0092] In summary, the key technical points of the present application are as follows:

[0093] 1) According to whether the laser Raman spectrum of paraffin on the Raman spectrum shows the vibration absorption peak combination of 1061, 1132, 1169, 1295, 1440, 1463, 2725, 2847, 2881, 2929 wave numbers, it is determined whether there is solid waxy petroleum of hydrocarbon components, and it is solid long-chain waxy petroleum;

[0094] 2) It is confirmed that there is naturally existing solid organic matter in the old pit seed jade raw stone, and it is solid long-chain waxy petroleum;

[0095] 3) According to the weak peaks of 3035±10, 3065±10 of Raman spectrum, it can be confirmed that there is trace amount of unsaturated hydrocarbon components in the solid waxy petroleum, which is less than 10%, and it is different from the resin glue containing 100% unsaturated hydrocarbons;

[0096] 4) According to the weak peaks of 1350±10, 1600±10 of Raman spectrum, it can be confirmed that there is trace amount of unsaturated hydrocarbon components in the solid waxy petroleum, which is less than 10%, and it can occur aging, carbonization and addition reaction under the action of laser focusing, generating disordered graphite (disordered carbon D peak) and ordered graphite (crystalline carbon G peak), and its Raman spectrum is obviously different from the resin glue containing 100% unsaturated hydrocarbons;

[0097] 5) The occurrence of solid waxy petroleum is the source of the bright and shining oil, the beautiful and shining oil, the bright and shining oil, and the bright and shining oil of the old pit seed oil, which is accepted by the jewelry industry, rather than the resin glue filled by artificial strong acid and strong alkali corrosion bleaching.

[0098] Although embodiments of the present application have been shown and described, it will be understood by those having ordinary skill in the art that various changes, modifications, alternatives, and variations can be made thereto without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. Raman spectroscopy detection method for waxy petroleum unsaturated components in Laokeng jadeite, characterized in that: The following steps are involved: S1: Prepare the polished and cleaned old pit seed jadeite sample; S2: Use a microscopic laser Raman spectrometer to locate solid organic matter in the sample at 500-1000 times magnification; S3: Acquire Raman spectrum data of micro-area fixed points; S4: Identify the following characteristic peak combinations: S41: wavenumber peak series of 2929±10, 2881±10, 2847±10, 2725±10, 1463±10, 1440±10, 1295±10, 1169±10, 1132±10, and 1061±10 characterizing long-chain waxy petroleum; S42: weak peaks at 3035 ± 10 and / or 3065 ± 10 (intensity < 10% of the reference peak) characterizing trace unsaturated components; S43: optional carbonization characteristic peaks at 1350±10 (D peak) and 1600±10 (G peak); S5: Determine the presence of natural solid waxy petroleum containing unsaturated components in the sample through the combination of characteristic peaks.

2. The Raman spectroscopy method for detecting waxy petroleum unsaturated components in old pit jadeite according to claim 1, characterized in that: The concentration of the unsaturated component is less than 10%, and the basis for determination is: The intensity ratio of the peaks 3035±10 and 3065±10 does not exceed 10% of the main peak (2929±10); When the 1600±10 peak exists, its half-height width is greater than 15cm -1 To distinguish it from the spikes of resin glue.

3. The Raman spectroscopy method for detecting waxy petroleum unsaturated components in old pit jadeite according to claim 1, characterized in that: The confirmation criteria for long-chain waxy petroleum is the simultaneous presence of: Fat chain characteristic peak groups: 2929±10, 2881±10, 2847±10; Characteristic peaks of crystalline region: double peaks at 1463±10 and 1440±10; Methylene rocking vibration peak: 1295 ± 10; Carbon chain skeleton vibration peak groups: 1169±10, 1132±10, 1061±10.

4. The Raman spectroscopy method for detecting waxy petroleum unsaturated components in old pit jadeite according to claim 1, characterized in that: The microscopic laser Raman test conditions include: Laser wavelength 532nm or 785nm; Power 0.5-5mW; Integration time 10-60 seconds; Spectral resolution ≤ 3cm -1 .

5. The Raman spectroscopy method for detecting waxy petroleum unsaturated components in old pit jadeite according to claim 1, characterized in that: It further includes the criteria for eliminating the interference of resin glue: The characteristic peaks of epoxy resin at 1111±5, 1185±5, and 1609±5 are missing; The peak intensity of 3035 / 3065 is more than 90% lower than that of the resin glue standard; 1700-1800cm does not exist -1 Carbonyl characteristic peak.

6. A method for identifying raw jadeite from old pits, characterized in that: The Raman spectroscopy detection method of the waxy petroleum unsaturated components of the old pit jadeite according to any one of claims 1 to 5 is used to confirm that: A naturally occurring waxy petroleum solid; The waxy petroleum contains 0.1-10% unsaturated components; Exclude artificial resin glue filling treatment.

7. The identification method according to claim 6, wherein: It further includes verifying the natural properties through the following distribution characteristics: Organic matter is dispersed in the mineral pores in the form of stars; Linear distribution of ice cracks in the grain boundaries of sodium aluminum pyroxene; The unique mesh filling structure without glue injection treatment.

8. A method for correcting jadeite detection standards, characterized in that: Jadeite that meets any of the test results of claims 1-7 shall be reclassified as: Grade A jadeite containing natural organic matter; Different from B / C grade jadeite that has been injected with glue.

9. A jadeite detection standard correction method according to claim 8, characterized in that: Specifically include: Revised the determination clauses for organic matter treatment in GB / T16553-2017; Establish a database of waxy petroleum characteristic peaks; Establish threshold standards for unsaturated component concentrations.

10. A new application of Raman spectroscopy detection equipment in jade identification, characterized by: The characteristic peak series of 2929±10, 2881±10, and 2847±10 for identifying natural waxy petroleum; Weak peaks of 3035±10 / 3065±10 used to distinguish natural unsaturated components from artificial resin glue; Used to detect the carbonization-derived doublets at 1350±10 (D peak) and 1600±10 (G peak).

Images