The microextraction/ion chromatographic (IC) method developed in this study involves extraction of 9 haloacetic acids (HAAs) from aqueous samples (acidified with sulfuric acid to a pH of < 0.5 and amended with copper sulfate pentahydrate and sodium sulfate) with methyl tert-butyl ether (MTBE), back extraction into reagent water, and analysis by IC with conductivity detection. The separation column consists of an Ion Pac AG-11 (2 mm id x 50 mm length) guard column and an Ion Pac AS-11 (2 mm id x 250 mm length) analytical column, and the concentration column is a 4 mm id x 35 mm length Dionex TAC-LP column. Use of the 2 mm id Dionex AS-11 column improved detection limits especially for trichloracetic acid (TCAA), bromodichloroacetic acid (BDCAA), dibromochloroacetic acid (DBCAA), and tribromoacetic acid (TBAA). The peak interfering with BCAA elutes at the same retention time as nitrate; however, we have not confirmed the presence of nitrate. Stability studies indicate that HAAs are stable in water for at least 8 days when preserved with ammonium chloride at 100 mg/L and stored at 4 degrees C in the dark. At day 30, recoveries were still high (e.g., 92.1-106%) for dichloroacetic acid (DCAA), BCAA, dibromoacetic acid (DBAA), trichloroacetic acid (TCAA), BDCAA, and DBCAA. However, recoveries of monochloroacetic acid (MCAA), monobromoacetic acid (MBAA), and TBAA were only 54.6, 56.8, and 66.8%, respectively. Stability studies of HAAs in H2SO4-saturated MTBE indicate that all compounds except TBAA are stable for 48 h when stored at 4 degrees C in the dark. TBAA recoveries dropped to 47.1% after 6 h of storage and no TBAA was detected after 48 h of storage. The method described here is only preliminary and was tested in only one laboratory. Additional research is needed to improve method performance.

Download full-text PDF

Source

Publication Analysis

Top Keywords

acid
10
haloacetic acids
8
ion pac
8
acid tcaa
8
stability studies
8
stored degrees
8
degrees dark
8
column
6
tbaa
5
determination haloacetic
4

Similar Publications

Stabilizing Lattice Oxygen of Bi2O3 by Interstitial Insertion of Indium for Efficient Formic Acid Electrosynthesis.

Angew Chem Int Ed Engl

January 2025

University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, No. 2006, Xiyuan Avenue, High-tech Zone (West Area), 610054, Chengdu, CHINA.

Bismuth oxide (Bi2O3) emerges as a potent catalyst for converting CO2 to formic acid (HCOOH), leveraging its abundant lattice oxygen and the high activity of its Bi-O bonds. Yet, its durability is usually impeded by the loss of lattice oxygen causing structure alteration and destabilized active bonds. Herein, we report an innovative approach via the interstitial incorporation of indium (In) into the Bi2O3, significantly enhancing bond stability and preserving lattice oxygen.

View Article and Find Full Text PDF

In recent years, alternative enzymes with varied specificities have gained importance in MS-based bottom-up proteomics, offering orthogonal information about biological samples and advantages in certain applications. However, most mass spectrometric workflows are optimized for tryptic digests. This raises the questions of whether enzyme specificity impacts mass spectrometry and if current methods for nontryptic digests are suboptimal.

View Article and Find Full Text PDF

Acid-Base Equilibrium of 5,5,6-Trihydroxy-6-Methyldihydropyrimidine-2,4(1,3)-Dione in the Gas Phase and in Water.

J Phys Chem A

January 2025

Ufa Institute of Chemistry, Ufa Federal Research Centre of the Russian Academy of Sciences, Laboratory of Physicochemical Methods of Analysis, 69 Prospekt Oktyabrya, Ufa 450054, Russian Federation.

The first-stage acid-base equilibrium of 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4(1,3)-dione was studied for the first time in aqueous solutions. Its constant (pK = 9.23 ± 0.

View Article and Find Full Text PDF

Efficient synthesis of dihydronaphthalenes cerium-catalyzed annulation of 1-alkoxy substituted 1-isochromenes with cinnamic acids.

Org Biomol Chem

January 2025

Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.

Dihydronaphthalenes play a crucial role in bioactive natural products and new drug discovery, and efficient and economic strategies to build them are needed. Herein, we disclose a highly efficient method to prepare dihydronaphthalenes a cerium-catalyzed cycloaddition of 1-isochromenes with cinnamic acids. This newly developed method not only features a broad and low-cost substrate scope and mild conditions but also exhibits very high functional group tolerance, including hydroxyl, borate ester and ester group substituents.

View Article and Find Full Text PDF

Desalting of oligonucleotides through precipitation for mass spectrometric analysis.

Nucleosides Nucleotides Nucleic Acids

January 2025

Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, ON, Canada.

Contamination of sodium ions in oligonucleotides often causes issues in mass spectrometric analysis. This study investigated the efficiency of the combination of ammonium acetate and alcohol in desalting oligonucleotides. It was found that oligonucleotide samples containing up to 4 M NaCl can be effectively desalted through precipitation with ethanol or isopropanol in the presence of 1 or 5 M ammonium acetate.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!