Influence of organic bases on the stability and separation properties of reversed-phase chemically bonded silica gels

Wehrli, A.; Hildenbrand, Jennie C.; Keller, Hubert; Stampfli, R.; Frei, R.W.

doi:10.1016/s0021-9673(00)80986-3

Cited by 156 publications

(35 citation statements)

References 6 publications

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“…This practice apparently is based on early studies with columns of certain silica supports [1,2]. These early studies showed that the rate of column degradation was dependent on the type of base and the concentration of organic modifier used in the mobile phase.…”

Section: Introductionmentioning

confidence: 99%

High pH mobile phase effects on silica-based reversed-phase high-performance liquid chromatographic columns

Kirkland

Straten

Claessens

1995

Journal of Chromatography A

156

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Section: Introductionmentioning

confidence: 99%

High pH mobile phase effects on silica-based reversed-phase high-performance liquid chromatographic columns

Kirkland

Straten

Claessens

1995

Journal of Chromatography A

156

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“…(ii) In a number of cases the properties of RP-HPLC phases change under practical laboratory conditions 5, 13,[21][22][23][24][25][26][27][28]. This is due to the influence of the eluent, which may affect the properties of the stationary phase by solvolysis of ligands, hydrolysis of siloxane bridges to silanols, hydrolysis of alkoxy-or chloro-groups of di-and trifunctional reagents and sorption of additives like ion-pairing agents from the mobile phase13.…”

Section: Introductionmentioning

confidence: 99%

Chromatographic and solid state nuclear magnetic resonance study of the changes in reversed-phase packings for high-performance liquid chromatography at different eluent compositions

Claessens

Haan

Ven

et al. 1988

Journal of Chromatography A

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“…We monitored relative retention time (retention time of analyte divided by retention time of internal standard) as an index of column performance and observed no significant difference in this parameter over a period of 6 months (0.707 + 0.020), during which time more than 400 samples were analyzed. This experience contrasts sharply with the rapid deterioration in column performance observed with unprotected reverse-phase columns exposed to a mobile phase with a pH of .9 (2,15). Although this technique is rarely used in clinical assays, our experience demonstrates its potential in reverse-phase applications that require a high pH.…”

Section: Discussionmentioning

confidence: 76%

“…between the pump and the injector. This precolumn was filled with spherical, unbonded silica which gradually dissolved in the flowing mobile phase, saturating it with silica and thus greatly reducing the loss of silica from the C18-bonded analytical column (2,15). We monitored relative retention time (retention time of analyte divided by retention time of internal standard) as an index of column performance and observed no significant difference in this parameter over a period of 6 months (0.707 + 0.020), during which time more than 400 samples were analyzed.…”

Section: Discussionmentioning

confidence: 99%

Ion pair high-performance liquid chromatographic assay for ceftriaxone

Granich¹,

Krogstad²

1987

Antimicrob Agents Chemother

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We developed a high-performance liquid chromatographic assay to measure ceftriaxone in serum, urine, and cerebrospinal fluid. Ion pairing was used because ceftriaxone is a relatively polar compound which is poorly retained on C18 columns in standard reverse-phase high-performance liquid chromatography and which produces trailing peaks in the absence of ion-pairing agents. The mobile phase was a combination of acetonitrile and water (46:54), adjusted to pH 9.0 with 10 mM K2HPO4, which contained 10 mM hexadecyltrimethylammonium bromide as the ion-pairing agent. Moxalactam (200 ,ug/ml) was used as the internal standard. A silica-packed precolumn (3 cm long) was used to prevent rapid deterioration of the analytical column (30 by 0.4 cm) by the alkaline pH of the mobile phase, and it significantly extended the life of the analytical column. The assay was linear with ceftriaxone concentrations of 1 to 250 ,ug/ml (r = 0.999) and correlated well with an agar diffusion bioassay (r = 0.990). Reproducibility was good, with intrarun coefficients of variation from 2.3 to 6.4% and interrun coefficients of variation from 3.2 to 21.4%. The absolute recoveries of ceftriaxone and moxalactam were 91 to 97 and 96 to 98%, respectively. No interferences were observed with more than 40 commonly prescribed drugs, including 10 cephalosporins (cefotaxime, cefoperazone, ceftazidime, ceftizoxime, cefoxitin, cefamandole, cephalothin, cefazolin, cephapirin, and cephalexin), br with sera from patients with renal or hepatic disease.Ceftriaxone is a new parenteral cephalosporin which exhibits potent activity against a variety of gram-negative and gram-positive bacteria (4), excellent penetration into extravascular spaces (7,12), and an increased resistance to degradation by ,B-lactamases (4). In contrast to other thirdgeneration cephalosporins, ceftriaxone possesses a greatly extended elimination half-life, on the order of 6 to 8 h (7). This prolonged half-life has positive implications for cost-effective antimicrobial therapy, allowing less frequent dosing and thus decreasing personnel and supply costs associated with parenteral drug administration both in the hospital (13) and in outpatient settings (9).Although bioassays represent the traditional approach to measuring antimicrobial concentrations in biological fluids, they vary widely in their turnaround time, specificity, and precision (8). In recent years, high-performance liquid chromatographic (HPLC) assays for ceftriaxone have been described which offer faster, more specific, and more reproducible results than bioassays for both pharmacokinetic studies and routine clinical monitoring (1,3,14). In this report, we describe an ion pair reverse-phase HPLC method for measuring ceftriaxone in serum, urine, and cerebrospinal fluid. In contrast to earlier HPLC assays (1, 3), this method incorporates an internal standard and requires a standard C18 reverse-phase column, which is used more frequently in clinical laboratories than are NH2 normal-phase columns (1). Since ceftriaxone is a highly pol...

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Influence of organic bases on the stability and separation properties of reversed-phase chemically bonded silica gels

Cited by 156 publications

References 6 publications

High pH mobile phase effects on silica-based reversed-phase high-performance liquid chromatographic columns

High pH mobile phase effects on silica-based reversed-phase high-performance liquid chromatographic columns

Chromatographic and solid state nuclear magnetic resonance study of the changes in reversed-phase packings for high-performance liquid chromatography at different eluent compositions

Ion pair high-performance liquid chromatographic assay for ceftriaxone

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