add concentration的用法和樣例：
例句
- The concentration ofL-serine and formaldehyde were determined by chromatic acid colorimetry.
采用鉻變酸比色法測定甲醛和絲氨酸濃度。 - Humic acid had significant photosensitization on tetramethrin,and itsphotosensitization increased rapidly as the humic acid concentration increased.
腐殖酸對胺菊酯光敏化作用顯著(zhù)，并隨腐殖酸濃度的增加而迅速增強。
