COSMOSIL πNAP shows stronger π-π interactions than phenyl columns. Its two fused aromatic rings retain nitrobenzene with more π ekectrons stronger than phenyl columns.

• Separation of tolunitrile isomers

• Separation of steroids

• Separation of tocopherols

Technical Note: Analysis of Cisplatin and its Variants in Water using COSMOSIL piNAP (PDF)

COSMOSIL πNAP uses a naphthalene-based bonded phase, and exhibits different retention behavior from C₁₈. In this note, πNAP is used to analyze cisplatin (CDDP) and its mono-chloro, none-chloro (hydration complex), and OH-dimer forms in water.

Standard C₁₈ columns have difficulty separating compounds of similar hydrophobicity. Perfomance may be improved by using Cholester, a column with improved molecular shape recognition.

Experiment Summary

Cisplatin (CDDP) in water converts to its mono-chloro, hydration complex, and OH-dimer forms, and it is thought that they exist in an equilibrium state (fig. 1). Each of these forms was separated and quantified.

Fig. 1. Equilibrium reactions of cisplatin (CDDP) in water
In water, CDDP loses Cl^-, which is replaced with water. Depending on the pH, it may be replaced by a hydroxide ion. The mono-chloro form may lose another Cl^-, and, in the same way, the water molecules (one or both) may be replaced with a hydroxide ion. These forms are in equilibrium.

Quantification of Cisplatin (CDDP) and its Mono-Chloro, None-Chloro, and OH-Dimer Forms

Comparing a C₁₈ column, COSMOSIL Cholester, and πNAP under identical conditions

When measuring the OH-dimer nitrate form, the dissociated NO₃^- peak elutes before the OH-dimer peak. C₁₈-MS-II could not separate the two peaks, and Cholester achieved partial separation, but could not separate to baseline. πNAP, however, was able to separate the compounds completely.

Analysis Using COSMOSIL πNAP

Below is a typical chromatogram; the peak separation was excellent. The calibration curve for cisplatin (CDDP) was linear in the range of 0.01 to 4 mM, and the CV values for within-day and between-day variation were within 5%.

Observations

By using COSMOSIL πNAP, it is possible to separate and quantify cisplatin (CDDP) and its mono-chloro, none-chloro, and OH-dimer forms using HPLC.

References

Kato R. et al. A Novel Analytical Method of Cisplatin Using the HPLC with a Naphthylethyl Group Bonded with Silica Gel (πNAP) Column. Biol Pharm Bull. 40(3), 290-296(2017). 

Data courtesy of Prof. Ryuji Kato, Ph D., Laboratory of Cardiovascular Pharmacotherapy and Toxicology, Osaka University of Pharmaceutical Sciences

Many of our columns feature aromatic ring-based stationary phases with strong π-π interactions, notably our πNAP (naphthylethyl) and PYE (pyrenylethyl) columns. Several other companies produce similar columns using a biphenyl phase, which has become a popular alternative to C₁₈ in recent years. Here, we compare these columns for several kinds of analysis.

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Phthalonitriles

Tocopherols

Nucleobases and Nucleosides

Sulfone Selectivity

Xanthine Derivatives (SFC)

Polyethylene Glycols (SFC)

Brochures

• COSMOSIL πNAP  (3.1 MB)
• COSMOSIL 2.5πNAP  (1.2 MB)
• Applications of Tocopherols  (231 KB)

Posters

• Evaluation of Pentabromobenzyl Stationary Phase for Separation of Polar Compounds by Reversed-Phase Chromatography
  (Poster from HPLC 2015, Geneva)
   (370 KB)
• STUDY OF ENHANCED π-π INTERACTIONS ON REVERSED PHASE HPLC COLUMNS.
  (Poster from HPLC 2008, Baltimore, MD)
   

COSMOSIL Application, which includes more than 7,700 applications using COSMOSIL/COSMOCORE columns, is now usable by clicking the link below which is in Nacalai Tesque, Inc. The application is searchable by sample category, sample name, CAS No., column name and particle size

New Application: Sesamin metabolites