Bases, HPLC analysis

Tables Deposition of collagen-glycosaminoglycan conjugates on poly(octadecen-a/f-maleic anhydride)-coated substrates. Fibrillogenesis and immobilization of fibrillar collagen (1.2 mg/ml) was performed for 2 h at 37 ° C in the presence of heparin and hyaluronic acid (0.4, 1.2 and 5.0 mg/ml, respectively). Thickness of the layers was determined ellip-sometrically using the refractive index of 1.6035 for the dried collagen layer. The collagen amount was determined by amino acid-based HPLC analysis after acidic hydrolysis of surface-bound collagen...

Before polyacrylamides are sold, the amount of residual acrylamide is determined. In one method, the monomer is extracted from the polymer and the acrylamide content is determined by hplc (153). A second method is based on analysis by cationic exchange chromatography (154). For dry products the particle si2e distribution can be quickly determined by use of a shaker and a series of test sieves. Batches with small particles can present a dust ha2ard. The percentage of insoluble material is determined in both dry and emulsion products. 

HPLC analysis showed complete conversion after 90 min. The use of less base resulted in longer reaction times. 

Figure 10. Reversed-phase HPLC analysis of PAHs extracted from SRM 1649, urban dust/organics, with UV detection, preceded by normal-phase HPLC fractionation based on ring carbon number. (Reprinted from reference 72. Copyright 1984 American Chemical Society.) Continued on next page.

Chromatographic Characterization of TTXs. The vast majority of reports have identified TTX and anhydro-TTX in bacterial cultures using HPLC, TLC, and GC-MS. Yasumoto et al. (30) showed that TTX-like substances extracted from a Pseudomonas sp. culture could bind to activated charcoal at pH 5.5 and be eluted with 20% ethanol in 1% acetic acid. In addition, HPLC analysis demonstrated TTX and anhydro-TTX-like fluorophors following strong base treatment. These compounds migrated on silica gel comparably to TTX and anhydro-TTX. Furthermore, when analyzed by electron ionization (EI)-MS and fast atom... 

How might these oligomers be produced in the fruit The easiest answer is that limited PG action on cell wall pectins generates them, and we have tested this point in vitro. CDTA- and Na2C03-soluble pectins and PGA (included as a positive control) were incubated with purified tomato PGl. Surprisingly, only the carbonate-soluble material and PGA were digested (based on HPLC analysis of reaction mixtures and generation of... 

Use of FID and SCD are compatible with SFE-HPLC, since they are flame-based and unaffected by gases in the mobile phase. Unfortunately, SCD can only be used with micro-HPLC (column i.d. <320 (tm), which requires miniaturised equipment not commonly found in most analytical laboratories. When following SFE with HPLC analysis using a spectroscopic detector, a medium-purity grade is usually sufficient. 

Islam, M.T., Majoros, I.J., and Baker Jr., J.R. (2005) HPLC analysis of PAMAM dendrimer based multifunctional devices. J. Chrom. B822, 21-26. 

Current commercial silica-based columns have two important characteristics (1) they can produce efficiency similar to that of columns packed with 3.5 /tm particles and (2) they typically produce a pressure drop of half that caused by a column packed with 5 /tm particles.35 Monolithic columns have been shown to exhibit flat van Deemter curves, resulting in little loss of efficiency at high flow rates.36 As a result, high-throughput separations on conventional HPLC instruments can be achieved by increasing flow rate up to nine times (up to 9 ml/min) the usual rate in a conventional packed column. Cycle times for HPLC analysis as short as 1 min (injection-to-injection) have been reported by users of monolithic columns. Additional benefits of monolithic columns cited include... 

FIGURE 15.1 Overview of configuration of MS and MS-based proteomic analysis. Proteins are extracted from biologic samples and fractionated by a variety of separation methods including gel separation, HPLC, and capillary electrophoresis. The common ion sources and mass analyzers used are indicated. 

Robot-based automated devices have been designed to perform HPLC injections (esp. off-line injections) unattended by pharmaceutical researchers. Each step of an HPLC analysis can be automated either by the robotic arm itself or by the use of a dedicated automated peripheral... 

The purity of all lipids and anthracyclines exceeded 98% based on thin-layer chromatography (TLC) and/or high-performance liquid chromatography (HPLC) analysis, performed as described by Barenholz and coworkers (38,49,50). 

---