Determination of Trace Bromate in Drinking Water with High Chloride Matrix by Cyclic Ion Chromatography

An ion chromatography (IC) system with switching recycling column was developed for the determination of bromate in drinking water with high chloride content. The system included a pump, two switching valves, guard column and analytical column, suppressor and a conductivity detector. In this method, the single eluent was used for both online collection and matrix elimination, and bromate was eluted from the concentrator column to the analytical column circularly. Under the optimized separation conditions, the method showed good linearity (r = 0.9995) in the range of 1–100 μg/L and repeatability (RSD ≤ 4.80%, n = 6). The limit of detection was 0.2 μg/L (S/N = 3) with 1000 μL sample volume injections. The method was applied to analysis of drinking and tap waters, and satisfactory recoveries of spiked samples between 96.8% and 108.7% were obtained. The result showed that the recycling column-switching system can be useful for the determination of traces of bromate in high-chloride samples, which is required in production of the drinking water and quality control of the final product.

Stability Indicating HPLC-ECD Method for the Analysis of Clarithromycin in Pharmaceutical Dosage Forms: Method Scaling versus Re-Validation

An isocratic high-performance liquid chromatographic method using electrochemical detection (HPLC-ECD) for the quantitation of clarithromycin (CLA) was developed using Response Surface Methodology (RSM) based on a Central Composite Design (CCD). The method was validated using International Conference on Harmonization (ICH) guidelines with an analytical run time of 20 min. Method re-validation following a change in analytical column was successful in reducing the analytical run time to 13 min, decreasing solvent consumption thus facilitating environmental and financial sustainability. The applicability of using the United States Pharmacopeia (USP) method scaling approach in place of method re-validation using a column with a different L–designation to the original analytical column, was investigated. The scaled method met all USP system suitability requirements for resolution, tailing factor and % relative standard deviation (RSD). The re-validated and scaled method was successfully used to resolve CLA from manufacturing excipients in commercially available dosage forms. Although USP method scaling is only permitted for columns within the same L-designation, these data suggest that it may also be applicable to columns of different designation.

Determination of progesterone compounds in the crude methanol extract of benalu duku leaves

Background and Aim: Dendrophthoe pentandra L. Miq (benalu duku) is a parasitic herb that commonly grows on the host plant Lansium domesticum. Researchers have found that the plant contains anticancer compounds and may contain phytoandrogens, including progesterone-like compounds, in its crude methanol extract. The objective of the current study was to investigate the compound of phyto progesterone in benalu duku leaves after extracted by methanol and prepared using an analytical column of high-performance liquid chromatography (HPLC). Materials and Methods: About 400 g of benalu duku leaves were pulverized, and their compounds were isolated by the isocratic method using an RP-18 analytical column (5 μm) with a mobile phase of 70:30 (methanol: water) in a photodiode array detector adjusted to 254 nm. The phyto progesterone compound was identified at a retention time of approximately 6.01 min. Results: By LC-electrospray ionization mass spectrometry focusing on molecular fractions, the fingerprint area of the Fourier transform-infrared spectroscopy (FT-IR, cm−1) and Hnuclear magnetic resonance (NMR) spectra indicated that the phyto progesterone product isolated was identical to the certified reference material of pure progesterone, particularly the specific functional groups in the FT-IR spectrum at wavenumbers of 1317.43 cm−1 and 1386.86 cm−1 and in the proton HNMR spectrum at carbon 21 of progesterone (p<0.05). Conclusion: Each 49.888 μg/mL of crude benalu duku leaf extract dissolved in the mobile phase contained 28.515±0.713 μg/mL phyto progesterone.