1. Optimization of the Cyanalyzer by Defining Maximum Sample Volume, Testing Durability of Adhesive, and Evaluating Micro-Solenoids
Natalie Boykoffa, Randy Jacksonb and Brian A. Logue*b a New York University b South Dakota State University
ABSTRACT
EXPERIMENTAL
RESULTS
Micro-Solenoids
Build circuit and write code
Design and test prototype for successful reagent delivery and cartridge ejection
Durability of Adhesive
Duration that the solutions sat did not damage adhesive
Pressure expended did not harm durability of adhesive
Cyanide, a fast acting, highly toxic chemical that inhibits ATP synthesis.1 Cyanide exposure may occur from a variety of sources.
Chemical Warfare Agent (CWA)
Essential reagent for industry and research labs2
Gas produced from burning polyurethane and vinyl during house fires3
Ingestion through foods such as almonds, spinach, and peach pits1
Micro-Solenoid
Even force, faster speed, less distance traveled compared to linear actuator
Reagent delivery comparable to manual delivery (see figure 7)
Figure 1: Cyanide ion
Figure 6: Stacked solenoids set to depress solution
RESULTS
The Cyanalyzer (see Figure 2) is a rapid, sensitive device that can test for low concentrations of cyanide from a blood sample.
Acidifies blood sample with sulfuric acid
Combines NaOH Base + Taurine + NDA to form fluorescent -isoindole product2
Takes fluorescence reading to determine
original concentration of cyanide
Potential Issues in manufacturing:
False positives as a result of overflow
Bubbles detaching from adhesive
Uneven force used for reagent delivery
Maximum Sample Volume
Addition of µL water had no overflow (see Table 2-5)
Excess water between trials led to error
Table 2: Water Volume = 80 µL.
Trial
Distance Bubbles Traveled (mm)
Observations 1
5mm
Few low bubbles, blood + water didn't mix to well, coagulation 2
6mm
Few low bubbles, still some coagulation, acid mixed early 3
8mm
Low large bubbles, a little coagulation 4
30mm + overflow
Large square bubble grow to cap, some overflow to gas chamber 5
Low bubbles, blood + water mixed well, no overflow 6
10mm mm
Large square bubbles rose high 7
7mm
Large low bubbles, no overflow, very little coagulation 8
Large low bubbles, no overflow, a little coagulation 9
9mm mm
Large low bubbles, no overflow, one tall bubble ~15mm, little 10
9mm
Large low bubbles, a little coagulation, no overflow
Figure 8: Solenoid set to eject cartridge
Figure 2: The Cyanalyzer
Figure 7: Comparison of solenoid reagent delivery to manual reagent delivery.
CONCLUSION
EXPERIMENTAL
There is roughly a 15 µL range of water volume added to the sample chamber before overflow is likely to occur. A disposable cartridge may eliminate error due to excess water remaining in the air flow channel between uses. Adhesive is more than appropriate for a disposable cartridge used for one blood sample. Solenoids provide successful delivery of reagent in comparison to the current linear actuator and delivers similar volume to volume delivered by hand.
Table 3: Water Volume = 85 µL.
Trial
Distance Bubbles Traveled (mm)
Observations 1
10mm mm
no overflow, blood + water were mixed well, no coagulation 2
10mm mm
no overflow a little coagulation, low large bubbles 3
10mm
no overflow, blood + water mixed well, no coagulation, low bubbles 4
9mm
no overflow, low large bubbles, very little coagulation 5
9mm mm
no overflow, a little coagulation, low large bubbles
Maximum Sample Volume
200 µL sulfuric acid + 15 µL blood + 80 µL water placed in sample chamber
Connected cartridge to air flow from Cyanalyzer and watched for overflow
Increased water volume by 5 µL increments until consistent reaction bubbles reached the top of the chamber
Table 4: Water Volume = 90 µL.
Trial
Distance Bubbles Traveled (mm)
Observations 1
9mm
no overflow, very little coagulation, low large bubbles 2
8mm mm
no overflow, a little coagulation, low bubbles 3
20mm
no overflow but a few bubbles made it to the very top 4
10mm mm
no overflow, most bubbles remained low but 3 bubbles almost rose to the top 5
10mm mm
no overflow, no coagulation, only two higher column bubbles
REFERENCES
Durability of Adhesive
Filled 2 sets of 24 bubbles with 8 different solutions (see Table 1)
Left one set for a one-week period
Depressed and refilled second set 50 times
Figure 3: Cartridge with sample chamber (right) and capture chamber (left)
Barilllo, D. J., (2009) Diagnosis and Treatment of Cyanide Toxicity. Journal of Burn Care & Research, Vol. 30, p DOI: /BCR.0b013e b91
Jackson, Randy, et al. “Development of a Fluorescence-Based Sensor for Rapid Diagnosis of Cyanide Exposure.” Analytical Chemistry (3), DOI: /ac403846s
Santiago, M., (2013) Pediatric Cyanide Poisoning by Fire Smoke Inhalation: A European Expert Consensus. Pediatric Emergency Care, Vol. 29, Issue 11, p DOI: /PEC.0b013e3182aa4ee1
Table 5: Water Volume = 95 µL.
Trial
Distance Bubbles Traveled (mm)
Observations 1
10mm mm
no overflow, a little coagulation, all low bubbles except one 15mm column bubble 2
10mm mm 3
15mm mm
no overflow, low bubbles or 15mm column bubbles, and a few 30mm columns 4
15mm mm
no overflow, 15mm columns and two 20mm column bubbles, mixed well 5
10mm mm
no overflow, mostly 10mm bubbles with a few reaching 25mm, well mixed
Table 1: Solution set up
ACKNOLEDGEMENTS #
Solution 1
H2O 2
Acid (2M H2SO4) 3
Ethanol 4
Base (0.1M NaOH + water) 5
NDA (0.002M methanol + water) 6
Taurine (0.05M buffer) 7
Methanol 8
Buffer
This work was made possible by the National Science Foundation REU Security Printing and Anti-Counterfeiting Site EEC
Special thanks to Dr. Boysen, Department of Humanities, SDSMT
Figure 5: Set of 24 bubbles