Alkalinity of diverse water samples can be altered by mercury preservation and borosilicate vial storage

Abstract

We compared the effects of preservation and storage methods on total alkalinity (AT) of seawater, estuarine water, freshwater, and groundwater samples stored for 0–6 months. Water samples, untreated or treated with HgCl2, 0.45 µm filtration, or filtration plus HgCl2, were stored in polypropylene or borosilicate glass vials for 0, 1, or 6 months. Mean AT of samples treated with HgCl2 was reduced by as much as 49.1 µmol kg−1 (1.3%). Borosilicate glass elevated AT, possibly due to dissolving silicates. There was little change in AT of control and filtered samples stored in polypropylene, except for untreated groundwater (~ 4.1% reduction at 6 months). HgCl2 concentrations of 0.02–0.05% reduced the AT of fresh, estuarine, and ground water samples by as much as 35.5 µmol kg−1 after 1 month, but had little effect on the AT of seawater. Adding glucose as a carbon source for microbial growth resulted in no AT changes in 0.45 µm-filtered samples. We suggest water samples intended for AT analyses can be filtered to 0.45 µm, and stored in polypropylene vials at 4 °C for at least 6 months. Borosilicate glassware and HgCl2 can be avoided to prevent analytical uncertainties and reduce risks related to use of Hg2+.

Assessment of the influence of benzalkonium chloride addition on radiocarbon analysis of dissolved inorganic carbon

“…Moreover, DIC concentrations, δ 13 C, and 14 C concentrations in natural waters sometimes vary despite refrigeration (Takahashi et al 2019 b ). Filtration is also effective (Doctor et al 2008; Takahashi et al 2019 a ; Wilson et al 2020; Mos et al 2021) as it has the advantage that water samples can be analyzed without contamination derived from chemical reagents. However, water samples containing a lot of suspended materials can clog the filter media, preventing their filtration.…”

Production of dissolved carbon and alkalinity during macroalgal wrack degradation on beaches: a mesocosm experiment with implications for blue carbon

“…DIC and DOC concentrations were measured with a TOC-V chp Shimadzu total organic carbon (TOC) analyser (Jones and Willett 2006). TA samples were collected into 40 mL polypropylene vials, stored at 4 °C until analysis, then determined via potentiometric titration (Mos et al 2021) with a Metrohm Titrino 848 Automatic Potentiometric Titrator. Prior to running the daily sample titrations, the titrator was run with seawater and in-house-standards (Dickson et al 2003), which allowed for daily corrections to ensure accuracy.…”

Differential effects of warming and acidification on chemosensory transmission and detection may strengthen non-consumptive effects of blue crab predators (Callinectes sapidus) on mud crab prey (Panopeus herbstii)

“…All pH probes (Cole-Parmer Oakton) for the CO 2 system were calibrated weekly, and water parameters (pH, temperature, salinity) were measured daily using a handheld Orion Star A325 meter with temperature-compensated pH and conductivity electrodes. Water samples were collected weekly from each tank, filtered using 0.45 mm filtration, and stored in polypropylene vials at 4°C for up to 6 months for later analysis of alkalinity (Mos et al, 2021). Total alkalinity was determined using a Hanna 901c precision automatic titrator and certified seawater standards (Dickson standard, Scripps Institution of Oceanography).…”