QuantiQuik™ L-Lactic Acid Quick Test Strips
- For rapid, direct determination of L-lactic acid concentrations in food and beverage samples as well as biological samples. Note: Requires access to pipettes for dilution. We offer pipettes that can be purchased separately: 20 uL Pipettes (Catalog: TP-20), 100 uL Pipettes (Catalog: TP-100), or 400 uL Pipettes. (Catalog: TP-400)
- Fast and sensitive. Use of 20 or 100 µL sample. Semi-quantitative measurement between 0-360 mg/L (undiluted) L-lactic acid.
- Convenient. No expensive lab equipment is needed.
- Sample treatment and assay can be performed in under 15 minutes.
- Wine, beer, milk, etc
- Approximately 15 min
- 10 tests
- 6 months
More DetailsL-LACTIC ACID, or L-lactate, is generated by lactate dehydrogenase (LDH) under hypoxic or anaerobic conditions. L-lactic acid is added to many foods and beverages to give them a tart flavor. Increased levels of L-lactic acid in milk, egg, and fruit juices can be an indication of spoilage. In the wine industry, increasing levels of L-lactic acid and decreasing levels of L-malic acid are monitored (Malolactic fermentation). In this process, the overall acidity of the wine is reduced and can lead to the improvement of the flavor of the wine.BioAssay Systems QuantiQuik™ L-Lactic Acid Test Strips are based on L-lactate dehydrogenase catalyzed oxidation of L-lactate in which the formed NADH reduces a chromogenic reagent. The intensity of product color is directly proportional to L-lactate concentration in the sample.
What samples have you tested?
The strips have been tested on red wine, white wine, homogenized whole milk, cultured buttermilk, almond milk, yogurt, beer, champagne, apple juice, lemonade, grape juice, orange juice, cranberry juice, lime and lemon juice.
My sample turns the strip very dark purple, how can I determine the L-lactate concentration?
Very dark purple indicates that the diluted sample concentration is greater than 360 mg/L. To obtain a more accurate concentration, the sample should be further diluted and retested. For example, if the sample was diluted 5×, try diluting 21×.
I don’t have access to a pipetteman. How can I accurately measure out my samples?
We offer exact volume transfer pipettes as an accessory. For samples requiring a 21× dilution, order the 20 µL transfer pipettes (TP20). For samples requiring a 5× dilution, order the 100 µL transfer pipettes (TP100).
Can I store unused reagents for future use?
Yes, unused reagents can be stored according to the assay protocol. The strips should be kept in a dry, cool location and protected from light.
I am using your test strips with fruit juice and the color only develops on the corners of the strips. I know there are high levels of L-Lactate in the juice, so the strips should be very dark. What is wrong?
The enzymes on the strips need to be around pH 7, and your fruit juice is likely pretty acidic. Adjust the pH of your samples with NaOH or another base until it is ~7, and rerun the strips. You may also want to try diluting the sample in water, since high levels of lactate can “max out” the strips. This will also help with the pH since water is 7.
Yokus, MA et al. (2019). Towards wearable electrochemical lactate sensing using osmotic-capillary microfluidic pumping. 2019 IEEE SENSORS, 1-4. Assay: L-Lactic Acid in model sweat.
Li, F et al. (2021). Limosilactobacillus balticus sp. Nov., Limosilactobacillus agrestis sp. Nov., Limosilactobacillus albertensis sp. Nov., Limosilactobacillus rudii sp. Nov. And Limosilactobacillus fastidiosus sp. Nov., five novel Limosilactobacillus species isolated from the vertebrate gastrointestinal tract, and proposal of six subspecies of Limosilactobacillus reuteri adapted to the gastrointestinal tract of specific vertebrate hosts. International Journal of Systematic and Evolutionary Microbiology, 71(2). Assay: L-Lactic Acid in fermentation cultures.
Saha, T et al. (2021). Wearable osmotic-capillary patch for prolonged sweat harvesting and sensing. ACS Applied Materials & Interfaces, 13(7): 8071-8081. Assay: L-Lactic Acid in model sweat.
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