Determination of heterocyclic aromatic amines (HAA) in commercially available meat products and fish by high performance liquid chromatography—Electrospray tandem mass spectrometry (HPLC-ESI-MS-MS)

Summary Ten heterocyclic aromatic amines (HAA) (1)–(10) were analyzed in commercially available meat products and fish. After sample preparation by Extrelut treatment and subsequent solid phase extraction applying propylsulphonic and C₁₈ silica cartridges, HPLC-ESI-MS-MS using selected reaction monitoring (SRM) and d₃-PhIP and d₃-MeIQx as internal and external standards, respectively, revealed the widely distributed presence of PhIP (8) and MeIQx (4), ranging from 0.1 to 5.3 ng g⁻¹ and 0.1 to 5.2 ng g⁻¹, respectively. Lower amounts were found for 4,8-DiMeIQx (5) and 7,8-DiMeIQx (6), ranging from 0.2 to 2.0 ng g⁻¹ and 0.1 to 0.2 ng g⁻¹, respectively. The other HAA under study, i.e. IQ, MeIQ, 4,7,8-TriMeIQx, Glu-P-1, and Glu-P-2 were not determinable under the experimental conditions used (determination limit 0.1 ng g⁻¹).     

Monitoring and Statistical Analysis of Formation of Organochlorine and Organobromine Compounds in Drinking Water of Different Water Intakes

The main drawback of drinking water chlorination involves the formation of quite hazardous disinfection by-products (DBPs), represented mainly by halogenated species. Based on the authors’ monitoring data since 2002, the prevalence of chlorine over bromine in the composition of volatile DBPs was shown for the drinking water in Ufa (Russia). However, the situation was completely reversed in the case of semi-volatile DBPs. The principal goal of the present study involved rationalization of the results of the long-term monitoring. Gas chromatography–mass spectrometry (GC-MS) was used for the qualitative and quantitative analysis of volatile DBPs. Identification of semi-volatile compounds was carried out with GC-MS, while gas chromatography with an atomic emission detector (GC-AED) was used for their quantification. A significant contribution of oxygen to the composition of semi-volatile compounds proves the decisive role of the dissolved organic matter oxidative destructive processes. Statistical analysis revealed notable linear correlations for trihalomethane and haloacetic acid formation vs. chlorine dose. On the contrary, halogenated semi-volatile products do not demonstrate any correlations with the water quality parameters or chlorine dose. Principal component analysis (PCA) placed them into separate groups. The results allow for proposing that formation of the organohalogenated species involved the fast penetration of bromine into the humic matter molecules and, further, their oxidative destruction by active chlorine.     

On-line monitoring of microg/L levels of haloacetic acids using ion chromatography with post-column nicotinamide reaction and fluorescence detection

A method for measuring the concentrations of the five regulated haloacetic acids (HAA5) in drinking water is reported. This method uses ion chromatography to separate HAA5 species, followed by post-column reaction with nicotinamide and detection of the fluorescent products. The result of method detection limit, accuracy, precision, linearity and interference studies are reported. The on-line monitoring method is compared directly to USEPA 552.3 in Memphis drinking water. Though not meant to replace the USEPA 552.3 for compliance monitoring, the proposed method does offer attractive alternatives considering the ease of automation and application of on-line monitoring directly from drinking water distribution systems.     

On-chip graphene oxide aptasensor for multiple protein detection

The versatility of an on-chip graphene oxide (GO) aptasensor was successfully confirmed by the detection of three different proteins, namely, thrombin (TB), prostate specific antigen (PSA), and hemagglutinin (HA), simply by changing the aptamers but with the sensor composition remaining the same. The results indicate that both DNA and RNA aptamers immobilized on the GO surface are sufficiently active to realize an on-chip aptasensor. Molecular selectivity and concentration dependence were investigated in relation to TB and PSA detection by using a dual, triple, and quintuple microchannel configuration. The multiple target detection of TB and PSA on a single chip was also demonstrated by using a 2 × 3 linear-array GO aptasensor. This work enables us to apply this sensor to the development of a multicomponent analysis system for a wide variety of targets by choosing appropriate aptamers.     

Researches on Formation of Haloacetic Acids in Chlorination of Drinking Water by a Novel Technique

Haloacetic acids (HAAs) are formed during the chlorination of drinking water, which are harmful to peo-ple′s health due to their carcinogenic and mutagenic effects. In the present study, a detection method combin-ing methyl tert-butyl ether (MtBE) extraction with acid catalysis and gas chromatography coupled with anelectron capture detector (GC/ECD) was developed for determining HAAs. The detection limit of this method(MDL) and relative standard deviation (RSD) were below 0. 37μg/L and 6.2%, respectively. The laboratorychlorination experiments were conducted with the purpose of investigating the influences of reaction time,temperature, UV254, bromide and ammonia-nitrogen on the formation of HAAs. The results show that theformation amount of HAAs increases with increasing reaction time and temperature, respectively;and thereexists a linear relationship between the formation of HAAs and UV254. The formation amount of HAAs de-creases first and then increases as the bromide ion concentration increases, and adding NH4^ is a possible wayto control the formation of HAAs.     

High performance liquid chromatography —Electrospray tandem mass spectrometry (HPLC-ESI-MS-MS) for the analysis of heterocyclic aromatic amines (HAA)

Summary Sensitive and selective detection of the sixteen most abundant heterocyclic aromatic amines (HAA) has been achieved by application of high performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS-MS) in combination with selected reaction monitoring (SRM). Detection limits between 0.1 and 50 ng mL^–1 were established by use of HAA model solutions.