Cwea Grade I Laboratory Analyst Exam Questions (169 Terms) With Verified Definitions Updated 2024

Endpoint of EDTA titrimetric method for hardness {Ans: Indicator turns red to purple, meaning all Ca and Mg have been chelated}Multiple tube procedure for enzyme substrate test {Ans: 1. Select number of tubes per sample 2. Aseptically add 10 mL sample to each tube, cap, and mix vigorously to dissolve 3. Incubate at 35 +/- 0.5 degree C Note: can also be performed where substrate media is added to the sample and dispensing into 5 20 mL or ten 10 mL sterile tubes}Concentration units for chemical and physical results {Ans: (mass units)/L}Drinking water set up {Ans: - 10 replicate tube each containing 10 mL - 5 replicate tubes containing 20 mL}Principle of E Coli bacteria for enzyme substrate test {Ans: Fluorogenic substrate is used to detect enzyme B glucuronidase, this enzyme hydrolyzes the substrate and produces fluorescent product when viewed under long wavelength UV light, this is a positive test.}Chain of custody should include {Ans: Sample number, signature of collector, date, time, and address of collection, sample type; sample preservation requirements; signatures of person involved in the chain of possession, and inclusive dates and times of possession}