HPLC-TSP

Successful combination of a chromatographic procedure for separating and isolating additive components with an on-line method for obtaining the IR spectrum enables detailed compositional and structural information to be obtained in a relatively short time frame, as shown in the case of additives in PP [501], and of a plasticiser (DEHP) and an aromatic phenyl phosphate flame retardant in a PVC fabric [502], RPLC-TSP-FTIR with diffuse reflectance detection has been used for dye analysis [512], The HPLC-separated components were deposited as a series of concentrated spots on a moving tape. HPLC-TSP-FTIR has analysed polystyrene samples [513,514], The LC Transform has also been employed for the identification of a stain in carpet yarn [515] and a contaminant in a multiwire cable [516], HPLC-FTIR can be used to maintain consistency of raw materials or to characterise a performance difference. 

Temephos was applied in a rice field of the Ebre Delta (Tarragona, Spain) via aircraft spraying at a rate of 250 ml/Ha. The calculated concentration range in the rice crop field water was between 41 and 125 fig/L. Only a maximum of 5.5% of the applied temephos was detected immediately following application. The analytical determination was performed using SPE followed by HPLC-TSP-MS in the PI mode (87). 

For the confirmation of PMFs in Valencia orange peel oil and juice, an HPLC method coupled with a thermospray mass spectrometry (HPLC-TSP-MS) detection system was utilized (112). A C 8 column (/zBondapak, 300 X 6-mm ID) was used with a mobile phase of H20-ACN (60 40, v/v) at a flow rate of 1.0 ml/min. Extract (20 fi1) was injected into the HPLC-TSP-MS system, and positive-ion spectra from m/z 100 to 700 were recorded at 1360 ms. Mass spectro-metric identification was done using positive chemical ionization (ICP). This technique allowed confirmation of the presence of eight flavones in the peel oils and seven flavones in the juice. 

Explosi ves, Dissolve in acetone or methanol elute explosive residues from HPLC column with methanol/ ammonium acetate HPLC/TSP/MS... 

The products were analyzed by HPLC (TSP Spectra Series), equipped with a Alltech Hypersil ODS column, and with a UV-Vis TSP UV150 detector (X 280... 

Reversed-phase HPLC-TSP-MS was used by Biitikofer et al. (1990) for the determination of glycerobenzoate derivatives of diradylglycerols of phospholipids. Neither intact phospholipids nor classes of polar lipids were determined. The PI moiety of the glycosylphosphatidylinositol (GPI)... 

Principles and Characteristics Thermospray ionisation (TSP) involves introduction of a relatively high flow (0.2-2mLmin ) of solvent into the ion source of a mass spectrometer, and is therefore suitable as an interface for HPLC-MS, using standard bore columns. A vaporiser probe (essentially a resistively heated capillary tube of about 100 xm i.d.) acts as a transfer line for taking solvent and solute into the source. The source is heated to prevent condensation of the solvent, and the temperature of the capillary is chosen so as to ensure vaporisation of the solvent. In this way, a vapour jet is generated, which contains small, electrically charged droplets if the solvent is at least partially aqueous and... 

The obvious alternative for the in-line flow-through cell in HPLC-FTIR is mobile-phase elimination ( transport interfacing), first reported in 1977 [495], and now the usual way of carrying out LC-FTIR, in particular for the identification of (minor) constituents of complex mixtures. Various spray-type LC-FTIR interfaces have been developed, namely, thermospray (TSP) [496], particle-beam (PB) [497,498], electrospray (ESP) [499] and pneumatic nebulisers [486], as compared by Som-sen et al. [500]. The main advantage of the TSP-based... 

Capillary HPLC-MS has been reported as a confirmatory tool for the analysis of synthetic dyes [585], but has not been considered as a general means for structural information (degradant identification, structural elucidation or unequivocal confirmation) positive identification of minor components (trace component MW, degradation products and by-products, structural information, thermolabile components) or identification of degradation components (MW even at 0.01 % level, simultaneous mass and retention time data, more specific and much higher resolution than PDA). Successful application of LC-MS for additive verification purposes relies heavily and depends greatly on the quality of a MS library. Meanwhile, MB, DLI, CF-FAB, and TSP interfaces belong to history [440]. 

During the last decade, research efforts in the field of LC-MS have changed considerably. Technological problems in interfacing appear to be solved, and a number of interfaces have been found suitable for the analysis of flavonoids. These include TSP, continuous-flow fast-atom bombardment (CF-FAB), ESI, and APCI. LC-MS is frequently used to determine the occurrence of previously identified compounds or to target the isolation of new compounds (Table 2.11). LC MS is rarely used for complete structural characterization, but it provides the molecular mass of the different constituents in a sample. Then, further structural characterization can be performed by LC-MS-MS and MS-MS analysis. In recent years, the combination of HPLC coupled simultaneously to a diode-array (UV-Vis) detector and to a mass spectrometer equipped with an ESI or APCI source has been the method of choice for the determination of flavonoid masses. Applications of LC-MS (and LC-MS-MS) in flavonoid... 

Much data on the structure of flavonoids in crude or semipurified plant extracts have been obtained by HPLC coupled with MS, in order to obtain information on sugar and acyl moieties not revealed by ultraviolet spectrum, without the need to isolate and hydrolyze the compounds. In the last decade, soft ionization MS techniques have been used in this respect, e.g., thermospray (TSP) and atmospheric pressure ionization (API). However, the most used methods for the determination of phenols in crude plant extracts were the coupling of liquid chromatography (LC) and MS with API techniques such as electrospray ionization (ESI) MS and atmospheric pressure chemical ionization (APCI) MS. ESI and APCI are soft ionization techniques that generate mainly protonated molecules for relatively small metabolites such as flavonoids. 

TSP was used in a so-called buffer ionization mode requiring the addition of a volatile buffer before vaporizing the HPLC eluate, and the discharge ionization mode that is based on a discharge electrode that produces a plasma of the HPLC eluent. LC-TSP-MS allowed the identification of several compounds from Tea C-glycosylflavone extracts and Citrus di-C-glycosylflavone mixtures. 

The coupling of HPLC to a mass spectrometer (MS) has provided for the ultimate in detection systems in terms of sensitivity and versatility. Betourski and Ballard (227) have used the techniques of thermospray TSP-LC-MS and tandem LC-MS-MS to obtain positive-ion mass spectra of two cationic dyes, Basic red 14 and Basic orange 14. According to Yinon et al. (228), TSP-LC-MS has been found to be a suitable technique for the analysis of dyes. It is sensitive and specific, and the ionization process is soft. One of the drawbacks, however, is that one obtains... 

The use of liquid chromatography-mass spectrometry (LC-MS) is becoming more popular because of the increasing number of LC-MS interfaces commercially available thermospray (TSP), particle beam (PB), and atmospheric pressure ionization (API). Coupled with mass spectroscopy, HPLC provides the analyst with a powerful tool for residue determination. 

An HPLC method for chlorogenic acids with lactones in six different commercial brands of roasted coffee was developed by Schrader et al. (143). Hydroxycinnamic acid derivatives, including mono- and di-caffeoylquinic acids, corresponding lactones, and feruloylquinic acids were extracted from coffee with methanol at 80°C for 1 h under reflux. An HPLC method using step-gradient elution with 2% aqueous acetic acid (eluent A) and ACN (eluent B) for a 75-min run time was developed. Determination was carried out by HPLC with UV detection at 324 nm, and further confirmation was conducted by HPLC-thermospray (TSP)-MS and HPLC-diode array detection. Elution order for mono-caffeoylquinic acid (CQA) was 3-CQA, 5-CQA, followed by 4-CQA, which was different from the usual elution order of mono-CQA (Fig. 17). These results indicate that it is currently not possible to predict the elution order of different reversed-phase packings due to the different selectivity (143). 

Cinchona alkaloids Qn, DQn, saccharine, benzoate TSP-LC-MS. RP-HPLC-UV at 254 nm. Column /zBondapack C18. Mobile phase CH3OH-ACN-H20-acetic acid (20 10 69 1, v/v/v/v). 

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