The phrase "acid was kept" is correct and usable in written English.
It can be used in contexts discussing the storage or handling of acid, particularly in scientific or safety-related discussions.
Example: "The laboratory protocol stated that the acid was kept in a secure cabinet to prevent any accidents."
Alternatives: "acid was stored" or "acid was maintained".
The 0.5% formic acid was kept to ensure appropriate acidity in order to keep the organic acids in their non-ionized state for chromatography.
Chitosan was first hydrated for 3 h, and then, after adding 1% (w/v) acetic acid, was kept in storage overnight with agitation until complete suspension.
In this investigation, different weight percentages of PVA (1, 2.5 and 4 wt%) and various slurry solid content (40, 50, 60 wt%) at three drying temperatures of the spray dryer (170, 200 and 230 °C) were employed while the content of phthalic acid was kept constant at 5 wt%.
CNC Preparation: To prepare the CNCs the wood pulp was dissolved in 64 w/w% sulphuric acid at 45 °C under continuous stirring for 1 h (ratio of cellulose to acid is kept at 1 9).
Only conserved blocks of amino acids were kept, leading to a 468-aa alignment.
Only conserved blocks of amino acids were kept after manual correction using GeneDoc, leading to a 633-aa alignment.
Confidently, aligned gap-free columns were then extracted using Gblocks with default settings (Castresana 2000), and only long alignments (≥100 amino acids) were kept for analysis.
For the cefotaxime/clavulanic acid combination, clavulanic acid concentration was kept constant at 4 mg/L.
The most intense signals of carminic, flavokermesic, and kermesic acids were obtained when formic acid content was kept in the range between 0.10% and 0.25%.
Fabric to acid ratio was kept as 1 20.
Acetic acid concentration was kept as minimum as possible to reduce the toxic effects.
