Direct compounding injection

Fig. 30. Design principles of direct compounding injection moulding machine for processing highly filled polymer compositions...

CU control unit DCIM direct compounding injection molding... 

Figure 5.8 Direct compounding injection moulding machine...

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

Direct liquid injection (DLI) has been used even less. Hirter et al. [579] have reported the early analysis of a synthetic antioxidant mixture (Irganox 1010/1076/1098) by means of iRPLC-DLI-QMS with Cl. In early studies, the HPLC effluent was vaporised by laser radiation [593] both El and solvent-mediated Cl spectra were obtained in the on-line mode from analytically difficult molecules. However, the instrumentation was complex the sensitivity was not as good as that obtained by GC-MS and thermal decomposition was observed with other compounds. This direct introduction approach with enrichment was used for the analysis of phthalates. 

Turbulent flow chromatography uses large particle packing materials and high flow rates to separate small molecules from proteins and other matrix components in plasma. In one example, Herman et al.109 reported that turbulent flow chromatography was useful for a series of discovery compounds as the online extraction step in LC/MS/MS analysis. As an alternative, Hsieh et al.89-104 107 described the use of a single mixed function column as a simpler process for direct plasma injection applications. 

Dough Moulding Compound Dynamic Mechanical Thermal Analysis Direct Resin Injection and Venting Differential Scanning Calorimeter Differential Thermal Analysis Elongation at Break... 

Analysis of aqueous solutions of the polar compounds (DCP, TCP, CA, and DCB) at concentrations of 1-10 ppm was easily accomplished by direct aqueous injection liquid chromatography. The Hamilton PRP-1 reverse-phase column gave a better resolution of these compounds than the conventional reverse-phase columns. Acetonitrile/water mixtures have been found to be as effective as the buffered mobile phases recommended by the manufacturer (28). Analyses of the nonpolar compounds (BHC and DEHP) at concentrations of 25-100 ppb were achieved by XAD resin adsorption-desorption, concentration, and GC techniques. 

The determination of OCP residues in milk has always presented problems, because the most common approach has required the total extraction of fat, together with lipophilic compounds, including organochlorine pesticide residues. Only one procedure for the extraction and separation of OCPs directly into an HPLC system has been described (11). The direct procedure injects the samples into an internal-surface reversed-phase C18 column connected online with the analytical column. 

In addition to the examples discussed above, a number of other xenobiotics are measured by their phase I reaction products. These compounds and their metabolites are listed in Table 20.1. These methods are for metabolites in urine. Normally, the urine sample is acidified to release the phase I metabolites from phase II conjugates that they might have formed, and except where direct sample injection is employed, the analyte is collected as vapor or extracted into an organic solvent. In some cases, the analyte is reacted with a reagent that produces a volatile derivative that is readily separated and detected by gas chromatography. 

Similarly, the calibration graph may be non-linear, particularly if peak heights are used as a quantitative parameter, and during manipulations with low concentrations of the solute when its adsorption on the surface of the support, column walls, etc., occurs to a significant extent. Fig. 1.2 illustrates the improvement that was obtained by the conversion of the sample compound. In the direct determination of morphine by GC, the dependence of the ratio of the peak height of morphine to that of squalene on the amount of compound injected is non-linear and therefore quantitative evaluation is difficult. An analogous calibration graph for the TMS derivative, in contrast, is linear. Hence, if a suitable derivative is used a drawback that could interfere with the GC analysis itself can be overcome [2]. 

The organic constituents of gaseous materials are determined either directly by injection of suitable aliquots of the mixture (up to 5 mL) into a gas chromatograph equipped with subambient temperature programming, or by adsorption onto polymer traps, e.g. Tenax. The direct method is usually suitable for organic compounds in concentrations of more than 1 ppm such as occur in process gas streams, while the adsorption method is more appropriate in trace gas analyses. 

It is particular concern in the analysis of aqueous samples, because the solvent effects involved during the direct aqueous injection (DAI) allow the direct analysis of levels ()ig l) of trihalomethanes and related compounds in water, using well deactivated thick film columns and E(D detection [19, 20 ]. 

Table I. Practical quantitation limits (PQL, ng injected), correlation coefficients (R2 and quadratic regression parameters (a and b) of 21 compounds with electron impact, and positive and negative chemical ionization (methane) Particle Beam mass spectrometry, direct flow injection with full scan mode...

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