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N-acetyltransferase 1 (NAT1) is a xenobiotic metabolizing enzyme that uses acetyl coenzyme A (AcCoA) as a cofactor for N-acetylation of many carcinogens including aromatic amines and alkylanilines. NAT1 is characterized by single nucleotide polymorphisms (SNPs) that may modulate affinity towards AcCoA. In the current study, we used Chinese hamster ovary (CHO) cells stably transfected with human NAT1*4 (reference allele) or NAT1*14B (variant allele) to measure AcCoA kinetic parameters for N-acetyltransferase activity measurements towards p-aminobenzoic acid (PABA), 4-aminobiphenyl (4-ABP), β-naphthylamine (BNA), benzidine and 3,4-dimethylaniline (3,4-DMA). Our results showed higher N-acetylation rates for each substrate catalyzed by NAT1*4 compared to NAT1*14B. NAT1*4 exhibited higher affinity to AcCoA when catalyzing the N-acetylation of BNA and benzidine compared to NAT1*14B. The results of the current study provide further insights into differences in carcinogen metabolism among individuals possessing the NAT1*14B haplotype.

The current research effort embodies the assessment of anti-bacterial potential of some N-substituted sulfonamides. The synthetic methodology was triggered by reaction of 2,4- dimethylaniline (1) with benzenesulfonyl chloride (2) at pH 9-10 in aqueous sodium carbonate (10 %) to generate N-(2,4-dimethylphenyl)benzenesulfonamide (3) which was further treated with different aralkylated halides (4a-e) in polar aprotic medium; N, N-dimethylformamide (DMF) and lithium hydride (LiH) which acts as base under stirring at room temperature for 3 hours to afford Naralkylated- N-(2,4-dimethylphenyl)benzenesulfonamides (5a-e). The proposed structures of sulfonamides were explicated via contemporary spectral methods e.g. IR, 1H-NMR, 13C -NMR and EIMS. Moreover, they were analyzed against different Gram (-) and (+) bacterial strains to unravel their inhibitory potential. The amalgamation of sulfonamide moiety with different aralkyl halides resulted in good anti-bacterial activity compared to standard; Ciprofloxacin. N-2-bromobenzyl-N- (2,4-dimethylphenyl)benzenesulfonamide (5d) and N-2-phenylpropyl-N-(2,4- dimethylphenyl)benzenesulfonamide (5b) contributed significantly which may be attributed to the successful and fruitful N-insertion of 2-bromobenzyl and 2-phenylpropyl moieties on parent sulfonamide. [ABSTRACT FROM AUTHOR]

We developed a method for the hydrolysis of amitraz, and its degradation products 2,4-dimethylphenyl-N′-methylformamidine (DMPF) and 2,4-dimethylformamide (DMF) into 2,4-dimethylaniline (DMA), directly from QuEChERS extracts. The hydrolysis product DMA was analysed using liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) in the positive ion mode with DMA D6 as an internal standard. Validation of DMPF and amitraz via DMA, following hydrolysis directly from the QuEChERS raw extracts, was performed at 0.05mgkg−1 and at 0.5mgkg−1. Individual recoveries of amitraz and DMPF, determined as DMA, ranged between 100 and 120% and between 96 and 118% respectively and the relative standard deviations (RSDs) below 5.2% and below 9.5% respectively (n=5 at each spiked level). Successful validation for amitraz, and DMPF at 0.01mgkg−1, was also conducted following fivefold pre-concentration of QuEChERS extracts prior to hydrolysis. Pear samples with a history of amitraz treatment, containing residues of the amitraz metabolite DMPF but no detectable residues of amitraz or its other metabolites, DMF and DMA, were extracted using the QuEChERS method. DMPF-results obtained using direct LC-MS/MS analysis were found to be comparable with DMA-results obtained when the same extracts were subjected to alkaline hydrolysis, suggesting that DMPF constituted virtually the only source of DMA in the analysed pears and that the determination of amitraz (sum) in pears does not necessarily require a cumbersome method involving cleavage to DMA. [ABSTRACT FROM AUTHOR]

N-acetyltransferase 1 (NAT1) is a xenobiotic metabolizing enzyme that uses acetyl coenzyme A (AcCoA) as a cofactor for N -acetylation of many carcinogens including aromatic amines and alkylanilines. NAT1 is characterized by single nucleotide polymorphisms (SNPs) that may modulate affinity towards AcCoA. In the current study, we used Chinese hamster ovary (CHO) cells stably transfected with human NAT1*4 (reference allele) or NAT1*14B (variant allele) to measure AcCoA kinetic parameters for N -acetyltransferase activity measurements towards p -aminobenzoic acid (PABA), 4-aminobiphenyl (4-ABP), β-naphthylamine (BNA), benzidine and 3,4-dimethylaniline (3,4-DMA). Our results showed higher N -acetylation rates for each substrate catalyzed by NAT1*4 compared to NAT1*14B . NAT1*4 exhibited higher affinity to AcCoA when catalyzing the N -acetylation of BNA and benzidine compared to NAT1*14B . The results of the current study provide further insights into differences in carcinogen metabolism among individuals possessing the NAT1*14B haplotype., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Habil, Doll and Hein.)

The EU maximum residue limit (MRL) definition for amitraz is ‘the sum of amitraz plus all its metabolites containing the 2,4-aniline moiety, expressed as amitraz’. A rapid and sensitive method has been developed and validated in-house for the determination of total amitraz in pears, strawberries, oranges and honey. Samples were hydrolysed (under acidic followed by alkaline conditions) to convert amitraz to 2,4-dimethyaniline, which was then partitioned into 2,2,4-trimethylpentane prior to quantification by gas chromatography–mass spectrometry. The method was validated at 0.02 and 0.1 mg kg-1 amitraz (well below MRL requirements) with a lowest calibrated level (LCL) for 2,4-dimethylaniline of 0.002 mg kg-1 (equivalent to 0.0024 mg kg-1 amitraz). A single partition step yielded recoveries of ∼60% (with % CV values in the range 3.3–8.2), which is satisfactory for screening purposes. A second partition increased recoveries by 10–20%, making the method suitable for the quantification of residues. [ABSTRACT FROM AUTHOR]

Abstract: Amitraz is a formamide acaracide used in the control of ticks and mites in livestock. An electrochemical method for the determination of total amitraz residues and its final breakdown product, 2,4-dimethylaniline, is presented. Cyclic voltammetry at a glassy carbon electrode showed the irreversible oxidation of amitraz and of 2,4-dimethylaniline. A linear current response was obtained with an extrapolated limit of detection of 2×10−8 M for amitraz and 1×10−8 M for 2,4-dimethylaniline. The biological degradation of amitraz and subsequent formation of 2,4-dimethylaniline was readily monitored in spent cattle dip. Amitraz and 2,4-dimethylaniline was also monitored in milk and honey samples. [Copyright &y& Elsevier]

Highly toxic residues of rocket fuel have been detected in the groundwater of an abandoned military missile base in north-west Estonia. The growth of indigenous rocket fuel-degrading bacteria in the polluted groundwater is strongly inhibited by a high concentration of pollutants in the groundwater. Two chemical oxidation processes, ozonation and catalytic wet oxidation (CWO), were studied for the treatment of such groundwater. The ozonation experiments were carried out in a wetted-wall column and the CWO experiments were conducted in an autoclave in the presence of granulated activated carbon. The ozone—water contact column operated at laboratory temperature whilst in CWO the operational variables ranged as follows: temperature from 413 to 446 K, oxygen pressure from 0.4 to 1 MPa. Both processes degraded the primary rocket fuel pollutant (dimethylanilines) and increased biodegradability. The solution remaining after ozonation and CWO contained mainly organic acids. Despite the formation of refractory compounds, the residual water can be treated in bioprocesses without complications because organic acids are easily biodegradable. [ABSTRACT FROM AUTHOR]

Abstract: An analytical method for the determination of amitraz residues in beeswax after hydrolysis to 2,4-dimethylaniline is reported. It consists of wax extraction with an acid buffer solution, head space solid phase microextraction and GC-ITD analysis. The limit of determination is 1ngg−1. Wax samples from beekepers and commercial foundations were analysed, content of residues varied from <1 to 20.5ngg−1. [Copyright &y& Elsevier]