Application of HPLC in the detection of anti-fouling agents in marine marine marine coatings

0 Introduction
high-efficiency liquid chromatography is a new separation analysis technology developed in the late 1960s on the basis of classical liquid chromatography and gas chromatography. In the late 1960s, with the development of chromatography theory, chromatography workers have realized that the use of particle fixation phase is an important way to improve column efficiency, liquid chromatography manufacturers, drawing on the experience of gas chromatography, successfully manufactured high-pressure infusion pumps and high sensitivity detectors, so that liquid chromatography has been reborn. HPLC method uses a full porous particle fixed phase, filled in a small diameter, stainless steel short column, the flow phase through the high-pressure infusion pump into the high column pressure column, the solute in the fixed phase propagation, diffusion speed is greatly accelerated, so as to obtain high column efficiency and high separation capacity
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in a short period of time.
HPLC can be used for the analysis of hard-to-volatile, highly polar substances. It is estimated that the GC (gas chromatography) method can only analyze about 20% of organic matter, while about 80% of organic matter can be analyzed using HPLC method. In the marine coating anti-fouling agent testing applications are also quite extensive, such as traditional organo tin coating release and metabolites in seawater content determination, due to environmental needs, in recent years in the determination of low-toxic anti-fouling coating additive release and metabolite content and non-toxic new anti-fouling agent development of separation testing has also been very widely used.
1 HPLC analysis of toxic coating anti-fouling agent organo tin
the early application of organo tin in marine anti-fouling coatings to suppress marine pollution has played a very effective role, but with the development of marine monitoring technology, the toxicity of organo tin and the harm to ecosystems are increasingly recognized by humans. For example, the gender distortions that lead to marine life seriously endanger the balance of ecosystems. There are many ways to analyze organo tin compounds. Because organo tin contains both metal elements and the properties of organic matter. Therefore, the current approach is to use organic technology such as GC, H PLC, supercritical fluid chromatography (SFC) with detection techniques such as atomic absorption (AAS), atomic emission (AES), and mass spectrometromety (MS). The concentration of organo tin in the marine environment is very low (10-12 to 10-9) and there is a wide variety, making it difficult to meet the requirements of high sensitivity and high selectivity analysis with traditional instruments. One of the more mature methods is to use GC as a means of separation, with a detector suitable for metal ion analysis.
H PLC can analyze organo tin that is not suitable for GC and is suitable for the direct separation of most polar and non-polar organo tin compounds. Compared with GC, H PLC has the following characteristics: First, without extraction and derivion, different forms of tin can be separated directly in the sample at room temperature, which not only shortens the analysis time, but also reduces the possible losses in the analysis process; Second, optimal separation can be obtained by changing the fixed phase and flow phase, and third, it is particularly suitable for separation and morphological analysis of biologically active compounds.
(1) high-efficiency liquid chromatography and atomic absorption (H PLC - AAS): Flame Atomic Absorption (FAAS) can be used directly with HPLC and provides on-line analysis.
HPLC usually flows at a flow rate of 0􀀁 5 to 2 mL/m in, while the flow rate from spray to AAS is generally 4 to 8 mL/m in, so the lift flow rate of column outflow and sprayer is usually balanced by adding solvents or gases to the T-type interface. Therefore, the spray device is the weakest link in the whole HPLC-AAS system, the atomization efficiency is often only 5% to 15%, in order to improve the sensitivity to organo tin, the post-column hydrogenation technology is often used. Compared with the low atomization efficiency of FAAS, the flame atom absorption method (GFAAS) of graphite furnace has an ideal sensitivity due to the high atomization efficiency of graphite furnace. However, due to the limitations of a single thermal cycle, the column outflow is completely dry at once, if connected online, 1200 oc or more of the continuous high temperature will burn out the quartz tube; Temperatures below 1 200 􀀁 can only determine hydrogenated organo tin, and the addition of a hydrogen generator makes the instrument connection cumbersome, so HPLC and GFAAS online use can only be designed as a semi-continuous split system. Factors affecting the combination include the effect of organic solvents and the problem of incomplete atomization, and the elimination method is the chemical reaction method of the pre-analysis solution. Re-optimizing the design of graphite furnace construction; Improve the surface of the graphite furnace and perform offline measurements. Compared with HPLC-FAAS, although HPLC-FAAS has the characteristics of simple operation and cheap price, but its check-out limit can not meet the needs. The DETECTION limit of HPLC-GFAAS is reduced by 3 orders of magnitude compared to HPLC-FAAS, and the interference of hydride substances is eliminated.
(2) High-efficiency liquid chromatography and plasma emission spectrum (H PLC - ICPAES) are used in a joint: the AES method, which uses inductive coupling plasma (ICP) as the excitation source, is more sensitive than various flame methods due to its high atomization rate. The AES spectrum has a wide linear range and can be measured with multiple elements at the same time. ICP-AES sample introduction system is mostly pneumatic atomization device, but the general atomization efficiency is only about 10%, and ICP on the introduction of HPLC organic solvents have pneumatic atomization, but poor tolerance, organic solvents often in the form of incomplete atomized aerosols gathered in plasma flame, greatly affecting the stability and excitation characteristics of the flame. Therefore, the main problem with ICP-AES in combination with HPLC is to try to overcome the spread of chromatography peaks caused by the low atomization efficiency and organic solvent effect. Using the properties of organocyc halides to form hydrogenators, HPLC-ICP-AES online determination of organo tin often uses in-line hydrogenation-derived methods, ICP atomizers as gas-liquid separators, thus achieving the goal of improving atomization efficiency and desolation and improving peak shape. The detection limit is up to ng level.
(3) high-efficiency liquid chromatography and plasma mass spectrometography (H PLC - ICP-MS): ICP is a very effective source of ions for MS. The ICP-M S is well matched to the flow rate of the HPLC flow phase (0􀀁 1 to 1 mL /m in). HPLC - ICP - M S is the most successful co-use system for organic metal morphological analysis. The many advantages shown by HPLC-ICP-MS co-use technology have attracted attention, resulting in an increase in research in this area in recent years. The main problem of ICP-M S system is the efficiency of the sprayer, the application of HPLC-DIN-ICP-M S system, with micro LC filling column and direct sample atomization system (DIN) to reduce the amount of organic solvents and reduce the volume to the extent that does not affect the peak width, etc. , these work in various forms of butyl tin, methyl tin, etc. , most of the detection of the lower detection limit of pg.
2 HPLC analysis of low-toxic organic anti-fouling agents in coatings
The current internationally recognized low-toxic organic anti-fouling agents are mainly enemy grass, Irgaro l 1051, Kathon 5287, TCMTB, TCMS, and this part of the substance is also used as an agricultural insecticide. To date, organic biocides have not been reported as anti-fouling in ships alone, and they are used only as anti-fouling agents for anti-fouling coatings such as copper and organo tin, so they are called organic anti-fouling agents. Copper compounds have anti-fouling activity on barnacles, tubeworms, and most algae, but are not effective for several algae such as moss, water clouds, and bent algae. Therefore, copper compounds as anti-fouling agents should be used in combination with other organic anti-fouling agents, so as to achieve a broad-spectrum anti-fouling marine attachment in anti-fouling paint.
2. 1 Enemy grass rumbling, Irgaro l 1051
Because enemy grass rumbling and Irgaro l 1051 are only u g/L in seawater and marine sediments, high sensitivity of high-efficiency liquid chromatography and low detection limits are suitable for determining such substances. GC can also determine the enemy grass rumbling, but before the determination needs to modify it to avoid heating decomposition, and HPLC law eliminated the modification of this step, so that the measurement step is simpler. Enemy grass rumbling mainly through HPLC quantitative, domestic use of HPLC - UV to determine the meat in the enemy grass rumble reported, the use of RP -C18 column, flow phase methanol: water : 1:1, UV detection wavelength 254 nm. H PLC-PDA can be used for both enemy grass and Irgano l 1051 at the same time detection, PDA is a type of ultraviolet detector, not only to obtain chromatography information, but also to obtain real-time spectral information of compounds. The new PDA detector provides high sensitivity detection at a high resolution of 1.2 nm for high-quality spectral information. These features can be used not only for high sensitivity detection, but also for spectral confirmation of compounds. In addition, multi-channel 2D chromatography can be collected, providing great convenience
to detect wavelengths of a wide range of different substances. The enemy herons and Irgalo l 1051 are used as antifouling agents, and degradation in seawater or sea mud is an important indicator for evaluating the long-term toxicity of anti-fouling agents. The content of enemy grass lynum and Irgalo l 1051 and their degradation products in seawater and sediments is mainly determined by H PLC-PAD.
many studies have shown that the products of Irgalo l 1051 photodegradation, biodegradation, and chemical decomposition are M 11, and that the degradation products of enemy grass rumbling under aerobic conditions include DCMU, DCPU, and DCA.
H PLC measurement method is: sea water and sediment sample HPLC determination conditions are about the same, protection column and extraction column filled Zo rbax SB - C18, column temperature 30 oc, flow phase composition of acetylene and water (M illiQ), by changing the composition of the flow phase within 25 m in from 20% acetylene to 100% acetylene gradient wash, flow rate of 1.7 m The diode array detector sets Irga ro l 1051 and M1 to 224 nm, and the enemy grass lychee and its metabolites to 244 nm. This test method obtains satisfactory recovery rates and detection limits for most substances in both seawater and sediments.
2. 2 Kathon 5287, TCMTB, and TCMS
literature studies have shown that HPLC is the most suitable method for determining K athon 5287. TCMTB thermal instability, can be indirectly determined by GC hydrolysing products, but there are still a series of interference problems to be eliminated, and the use of HPLC does not need to TCMTB hydrolysing to determine TCMTB, the method is easier. Moreover, HPLC -UV (high-efficiency liquid chromatography-UV detector) can also be simultaneously measured by TCMTB and TC-M S, with a detection limit of 1,000 ng/L. The H PLC-APC I-M S (High-Efficiency Liquid Chromatography Atmospheric Pressure Chemical Ionologic Mass Spectrometrometrography) method also provides a lower detection limit, and the mass spectrometrator can detect more samples simultaneously, with high sensitivity, and obtains a large and rich structural information different from conventional HPLC detectors.
Atmospheric Chemical Ionization (APCI) is a spray-type soft ionization technology (the resulting simple mass spectrometography after ionization is often composed of protonized molecules ( M - H ) and negative protonized molecules ( M - H ) - its high ionization efficiency has become the most ideal LC/M S interface. It is highly sensitive and can detect proteins less than 1 pimol and dozens of pigotic pesticides.
HPLC-APC I-M S is currently the most effective method for analyzing low-concentration substances in the environment, such as pesticides. Based on the advantages of HPLC and LC/APCI/M S, K athon 5287, TCMTB, TCMS slugs, and enemy grass sloppy can be analyzed simultaneously through HPLC-APCI-MS. The usual method is: first using C18 column for solid phase extraction, and then using inverse high-efficiency liquid chromatography - polarity conversion atmospheric pressure mass spectrometrometrometromet for quantitative qualitative analysis of samples.
HPLC conditions: USENV inverse column, column temperature: 50 oc, flow phase: acetylene: water: 10:90, injection 25 uL sample balanced with the flow phase 5 m in, flow phase linear change to 100% acetylene gradient wasced.
mass spectrometric condition: positive ionoes, Corona 3􀀁2 kV, high-voltage lens 0 kV, ion energy 2.0 V; negative ion, corona 1.8 kV, high-voltage lens 0 kV, ion energy 2.0 V; source temperature 150 oc, probe temperature 400oc, low mass resolution 12.5, high-quality resolution 12.5, ion energy 2.0 V.
HPLC-APCI-M S detection limits can be up to ng/L, kathon 5287 can reach 1 ng /L, TCMTB can reach 1 ng /L, TCM S can reach 5 ng /L. This method can be used to sensitively analyze the concentration of 3 anti-fouling additives in different docks in the sea area, so as to evaluate them.
3. HPLC-UV detection of the new non-toxic coating anti-fouling agent capsaicin
capsaicin is widely used in the food industry and pharmaceutical fields, while capsaicin can be used as a natural agricultural insecticide, because its insecticidal anti-fouling efficacy is currently also used in marine anti-fouling coatings, is a new non-toxic anti-fouling agent in recent years. Although this kind of non-toxic anti-fouling agent does not have the substance to kill biological activity, but has a high degree of anaesthetic, avoidable and hinders the adhesive performance.
capsaicin