Merilyn Manley-Harris

α‑Ribazole is an essential component of a recently developed cyanide-free method for vitamin B12 determination, but application of the method is limited by the lack of a commercially available α‑ribazole standard and the difficulty of its reliable in-house preparation. This study evaluated and optimised a previously reported preparation of α‑ribazole from cyanocobalamin, focusing on the chemical hydrolysis and boronate affinity chromatography (BAC) clean-up steps. Implementation of the previously published protocol in our laboratory did not reproduce the reported yield, prompting systematic investigation of key variables, including hydrolysis conditions and BAC eluent composition and volume. The optimised method, incorporating acid hydrolysis (hydrochloric acid, 1.5 M) and stronger BAC elution conditions, substantially improved α-ribazole recovery. An acetonitrile-modified formic acid solution (20:80, v/v, 1.0 M) enhanced elution efficiency from the boronic acid gel, and the final protocol achieved an overall yield of 76%. The identity of the product was confirmed by comprehensive 2D nuclear magnetic resonance and mass spectrometric analyses. The improved procedure provides a more robust and reproducible route for α-ribazole preparation and facilitates broader use of cyanide-free vitamin B12 analysis.

When Cu(II) reacts with ascorbic acid (AA) to form Cu(I), Cu(I) can combine with eosin Y (EY) to form ionic associations, resulting in significant fluorescence quenching of the EY. Based on the turn-off of fluorescence in the chemosensor EY, a green reaction is proposed herein for the detection of Cu(II). The novel detection method for Cu(II) demonstrates simplicity, high sensitivity, and excellent selectivity, rendering it suitable for analyzing environmental samples. A static fluorescence quenching mechanism is validated through the Stern–Volmer relationship, and the thermodynamic parameters of the reaction are explored using a van 't Hoff plot. The reaction mechanism is investigated via fluorescence spectra, absorption spectra, and density-functional theory (DFT) calculations. The probe's green nature is confirmed by applying four green analytical chemistry metrics.

The free biologically active estrogenic steroid hormones (ESHs), 17α-estradiol, 17β-estradiol and estrone were analysed in the liquid and solid phases of a covered anaerobic pond (CAP) dairy farm effluent treatment system. The total mean concentration of ESHs measured in the CAP influent, sludge and effluent were 4,171, 93,601 and 4,346 ng/L respectively. Peak ESH concentrations were measured in dairy shed effluent during April and July, which correlated with the late pregnancy and calving periods on the farm, under study. The mean organic carbon normalised adsorption coefficient (K oc ) calculated for ESH in the samples from the CAP system ranged between 3.06 to 3.78 mL/g and are comparable with published values for K oc in soil and wastewater sludge. Up to 99% of the total mass of ESHs in the samples were retained in the solids phase, demonstrating the importance of considering this fraction within dairy farm effluent treatment systems. The predominant ESH in the influent samples was 17α-estradiol (2,869 ng/L), but estrone predominated in the CAP sludge (85,414 ng/L) and effluent (3,140 ng/L). Anaerobic treatment of dairy waste decreased 17α-estradiol and 17β-estradiol while increasing estrone. Regardless, estrogenic equivalents of the dairy waste were dominated by the contribution of 17b-estradiol.

Summary: Current models of floral nectar production do not include a contribution from photosynthesis by green nectary tissue, even though many species have green nectaries. Mānuka (Leptospermum scoparium) floral nectaries are green, and in addition to sugars, their nectar contains dihydroxyacetone (DHA), the precursor of the antimicrobial agent in the honey. We investigated causes of variation in mānuka floral nectar production, particularly the effect of light incident on the nectary. Flower gas exchange, chlorophyll fluorescence, and the effects on nectar of age, temperature, light, sucrose, 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU), pyridoxal phosphate, and ¹³CO₂, were measured for attached and excised flowers. Flower age affected all nectar traits, whilst temperature affected total nectar sugar only. Increased light reduced floral CO₂ efflux, increased nectar sugar production, and affected the ratio of DHA to other nectar sugars. DCMU, an inhibitor of photosystem II, reduced nectar sugar production. Pyridoxal phosphate, an inhibitor of the chloroplast envelope triose phosphate transporter, reduced nectar DHA content. Incubation of excised flowers with ¹³CO₂ in the light resulted in enrichment of nectar sugars, including DHA. Photosynthesis within green nectaries contributes to nectar sugars and influences nectar composition. Mānuka nectar DHA arises from pools of triose phosphate that are modulated by nectary photosynthesis.