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Laboratory

Measuring Vape Cartridge Success with N.N. Analytics  

After exploring the reasons why vape cartridges fail in our previous blog post, it’s time to dive into the science of measuring vape cartridge success. Joining us again is Jake Rubenstein, the President and CEO of N.N. Analytics. In this blog, Jake shares his expertise on how Vape-Jet, N.N. Analytics, and other contributing factors ensure your cartridges perform at their best for a premium vaping experience. 

What Leads to a Vape Cartridge Success?  

Before we get into the finer scientific details of vape cartridge success, we should look at the factors that lead to a premium vaping experience. Here are the key elements that contribute to successful vape cartridges we’ve seen at N.N. Analytics:  

  • Ensure your vape cartridge performs the same when full, half-full, or near empty without leaks, clogs, or dry hits. 
  • Correct amount of delivered aerosol—correct standard Aerosol Collected Mass (ACM) between 25 to 60mg/puff in most vaping applications measured under a standard ISO regimen.   
  • Low-Pressure Drop (PD) values—a properly assembled cartridge with an oil that has a matched rheology will not have a high PD value when compared to a control sample.  
  • Lack of leaks through the 510 center-post—minimal device weight loss (DWL) is measured throughout the lifetime of a cartridge that was not captured or measured as Aerosol Collected Mass (ACM).
  • Lack of evaporation through the 510 center-post—minimal device weight loss (DWL) as measured throughout the lifetime of the cartridge that is not captured and measured as Aerosol Collected Mass (ACM). 
  • Lack of leaks into the center post by way of the failure modes identified above. 
  • Lack of leaks through the mouthpiece by way of the failure modes identified above.  
  • The proper delivery of cannabinoids measured in the Aerosol Collected Mass (ACM) without deterioration by way of elevated coil temperatures and a lack of airflow through the cartridge.   

What variables are critical for vape cartridge success?   

  • Choosing reliably vetted hardware with a proven track record and direct relationships with a trusted analytical lab.    
  • Confirming the compatibility between each type of cannabis oil and the hardware you intend to fill.   
  • Standardizing your formulation and enforcing process control throughout your extraction and filling operation to reduce variability in your oil output as measured by standard rheological assessments on a batch-by-batch basis.   
  • Confirming that the batch-to-batch variance does not fall outside of the approved rheological bracket defined for the cartridge-oil combination.   
  • A collaborative effort with open communication between the vape hardware manufacturer, vape filling machine manufacturer, vape testing facility, and you.   
  • The Vape-Jet product support team can tailor your filling temperatures and speeds to your formulation. N.N. Analytics can also develop and confirm with Vape-Jet the correct filling parameters that will support ideal cartridge performance without failure.  

How N.N. Analytics Can Resolve Your Vape Cartridge Failures

N.N. Analytics facilitates the standardization of oil-hardware combinations with characterization testing. Our approach to resolving your vape cartridge failure challenges comes in two phases.    

Phase One: Establishment of Approved Parameters    

Rheology Characterization and Performance Assessment of Solutions for Cartridge Filling—this is where we characterize the oil solutions to understand how they perform in each hardware SKU. In short, this process helps us understand whether known rheology will affect the performance and failure rate of the cartridge part number that is approved for sale.    

Failure Mode and Effects Analysis: Cartridge Performance Assessment (Leakage & Dry Hits)—we use this standard metric to evaluate a new part number in hardware that we haven’t assessed yet. We evaluate stability performance, including device weight loss, pressure drop, and aerosol collected mass. This testing is performed with standard solutions (oils) that are deployed by NN Analytics, meeting the criteria of low, medium, or high viscosity:  

  • Low Viscosity: Akin to rosin formulations or those with terpene additions of greater than 10%  
  • Medium viscosity: Akin to formulations that have a standard number of terpenes and are standard performers – This is our target range for most formulations  
  • High Viscosity: High potency oils with minimal terpene or diluent additions require optimum shear rates of cartridges tuned to high-viscosity oils.   

Phase Two: Continual Evaluation of Approved Ranges    

Stability Studies—used to evaluate the stability performance of a new batch of hardware by ACM/DWL and by delivered cannabinoid concentrations in the ACM.   

Oil Performance Assessment—used to evaluate a new batch of oil manufactured to a specific recipe by rheological assessment and terpene/cannabinoid measurements in the ACM according to the standard (approved) reference sample. 

Standard Measurements We Use at N.N. Analytics 

Device Weight Loss   

Device Weight Loss (DWL) measures the total change in filled mass of oil in a cartridge. This measurement is taken when the vape cartridge is filled and capped at T=0, then monitored throughout the lifetime of the cartridge during testing or stability studies before Aerosol Collected Mass (ACM) measurements are taken. 

Over time, oil may leak or evaporate due to leakage or evaporation from an improper cap seal or airhole feed size that allows atmosphere to enter the vape cartridge by way of the center post or air inlets at the bottom of the cartridge, leading to reduced ACM, evaporation of volatile terpenes, and possible oxidation of cannabinoids. 

DWL and reduced ACM are both causative variables of leakage that causes oil to emit from the 510 thread or air feed holes, which are indicative of a rheological mismatch of the oil viscosity with the hardware, namely:   

  • coil-wicking material porosity    
  • feed hole size    
  • airflow hole size    
  • Improper oil rheology  

Aerosol Performance   

Aerosol collected mass (ACM)—this variable determines the efficiency of the cartridge as a complete unit that will establish a parameter we call “ACM” for the amount of vapor emitted from the cartridge during normal expected vaping conditions.   

ACM can be influenced by many factors and is considered a correlative variable for cartridge performance rather than a causative variable, such as device weight loss (DWL) or pressure drop (PD).  

Aerosol Constituents   

There are many constituents in cannabis and hemp aerosol, which we can classify as indicative of proper or improper performance. These measurements are taken hand-in-hand with aerosol collected mass (ACM) to understand the correct selection of good oil and hardware combinations during expected vaping conditions (ISO and CORESTA methods) and identify failures during vaping that may lead to emissions of harmful or potentially harmful constituents (HPHCs), such as:   

  • Heavy Metals    
    • Tested using ICP-MS    
      • Chromium (stainless steel parts or coil)    
      • Nickel (coil)    
      • Cadmium (stainless steel parts or coil)    
      • Lead (coil solder)  
  • Aldehydes    
    • Tested using GC/MS    
  • Volatile Solvents    
    • Tested using GC/MS    
  • Microplastics and solvated plastics    
    • Tested using LC/MS    
  • Other foreign material (coil-wicking material including ceramic particles, rayon, or cotton fibers)     
    • Tested by Scanning Electron Microscopy Tandem Energy-Dispersive X-Ray Spectroscopy (SEM/EDX)  

Guaranteeing Vape Cartridge Sucess: Measuring Solution Rheology and Cartridge Performance  

How do vape cartridge producers guarantee their solution will not leak when choosing new cartridge hardware?    

The way to guarantee that leakage will not occur is to standardize the minimum “thickness” of the solution used in a particular hardware platform. N.N. Analytics accomplishes this with strict measurements of solution rheology to define the viscosity, shear rate, and elasticity of oils using an iso-accredited method for rheology measurements.    

Additionally, N.N. Analytics measures coil performance by deploying its patent-pending Iron Lung aerosol collection technology to assess aerosol performance by measuring pressure drop, capturing the aerosol, and measuring the total weight and constituents within the aerosol. Pressure drop measurements allow us to evaluate leakage preventing aerosol delivery. Aerosol weight measurements allow for the characterization of atomizer/coil performance.    

N.N. Analytics' patent-pending Iron Lung aerosol collection technology
N.N. Analytics’ patent-pending “Iron Lung” aerosol collection technology

How can vape cartridge producers guarantee their solution will feed well when choosing new cartridge hardware?    

The way to prevent dry hits is by standardizing the maximum thickness of the solution in a particular hardware platform.    

Unleash Your Vape’s True Potential with Vape-Jet & N.N. Analytics

As you can see, the science behind a successful vaping experience requires cultivating a unique balance between the formulation of the oil, the hardware used, and the filling process.   

At N.N. Analytics, we use a combination of measurements to ensure that your vape cartridges perform optimally and meet industry standards. Our expert team works closely with you, the vape hardware manufacturer and the vape filling machine manufacturer to resolve your vape cartridge failure challenges. Let N.N. Analytics help you achieve the premium vaping experience your customers deserve.  

N.N. Analytics Full Service E-Liquid Testing Laboratory | Click to Browse Our Services

Need some help taking your vape cartridge filling performance to the next level? Reach out to our crew and learn how Vape-Jet can provide next-level products for your customers.  

Some of our success stories:  

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Laboratory Uncategorized Vape-Jet

Vape-Jet Know-How: Optimize Your Live Resin Process

As vape cartridge markets mature and consumers develop more discerning tastes, manufacturers are switching from botanical terpene flavored distillate to true-to-strain cannabis-derived terpene, “live resin” formulations. While this might seem like an easy switch, producing live resin is a complex process that demands, like everything cannabis, we follow best practices. 

Who am I to discuss such complexities? Vape-Jet COO Devon Reid, at your service. I am a chemist and engineer with a passion for optimizing workflows and fostering better customer experiences with science.  

With the release of our brand-new Vape-Jet 4.0, making vape cartridge filling easier than ever (and since preparing quality cannabis products is my area of expertise), I’m using this space to guide you through the switch to live resin. If you want to produce some pure, Walter White-esque, cannabis cartridges with your Vape-Jet, you’ve come to the right place. 

Devon Reid on the set of Breaking Bad.
Speaking of Walter White, here’s a shot of Devon on the set of Breaking Bad from Walter’s brother-in-law Hank’s backyard.

Let’s talk chemistry. 

Common Problems When Switching to Live Resin

If a manufacturer already produces traditional extract products in-house—via hydrocarbon (BHO) or rosin extraction—the switch to using these products as a feedstock for live resin or sauce cartridges seems simple. Unfortunately, compared to cartridges filled with pure distillate and isolated terpene blends, preparing live resin extracts for vape cartridge production presents unique challenges.  

Vape-Jet: The most advanced fully-automatic vape cartridge filling machine. Click to learn more.
Why are pure distillate operations easier than live resin formulations? 

When filled with a Vape-Jet, distillate-based formulations are a breeze. Since THC distillate is incredibly pure (typically over 90%), it performs reliably from batch to batch, especially when formulated with known quantities of isolated, botanical terpene blends. Why? Because THC distillate contains few extraction byproducts, making it thermally and chemically stable. 

In short, when we mix distillate with isolated terpenes, there is not much else in the formulation that can change how it behaves under heat and pressure. As a result, the formulation is chemically simple, which is why distillate performs so well during filling.  

Because of chemical simplicity and process predictability, Vape-Jet operators can use as little as 50C of heat and 50 to 60PSI of nitrogen pressure. This is almost half as much heat as other vape cartridge fillers, which cannot operate under pressure. With the ideal filling conditions made possible by a Vape-Jet, cannabinoids and terpenes are preserved from thermal degradation and oxidation, ensuring consistent product quality and filling speed. 

Unlike simple distillate, live resin and rosin extracts are unrefined, containing a complex mixture of extraction byproducts like lipids, phospholipids, chlorophyll, and carotenoids (in addition to cannabinoids and terpenes). These extraction byproducts result in a highly variable mixture depending on batch, strain, growing conditions, and extraction variables—never a good thing for quality control or scaling your production process. 

Why can’t you just decarboxylate the extract and start filling?

First, we’ll start with the basics. Decarboxylation is the process of removing a carboxyl group from the cannabinoid, converting THCa to THC. Removal typically takes place before or during the distillation process during which vacuum conditions efficiently remove the carboxyl group, in the form of CO2, from the oil.  

While it is certainly possible to just decarboxylate bulk extract and fill cartridges, optimal filling parameters will be wildly different because of the variability in batches and strains discussed above. Some cons could be degraded terpenes (burnt taste), degraded cannabinoids (reddish or dark appearance), and reduced filling throughput. In the extreme case, several critical dispensing errors—from pump stalling to bubbly cartridges and lost product—can result. 

Can I decarboxylate bulk, unrefined extract without vacuum pressure

Not a great idea. Without a vacuum, you’ll need a very long stirring and heating process to remove CO2. This usually means a substantial loss of terpenes to evaporation and oxidation, muting the flavor and darkening the color of the vape cartridges.  

Because cannabinoids are degraded and terpenes are lost, increased oil viscosity results in slower fill times. Furthermore, if this “no-vacuum-decarboxylation process” is rushed, CO2 left in the solution will be agitated during the filling process, potentially leaving cartridges riddled with bubbles in the best case and spilling out of the cartridge in the worst case. 

The Solution: Upstream Changes 

The complexity of live resin formulations, especially rosin, makes them less predictable than distillate and isolated terpene formulations. For example, live resin formulations with terpene concentrations over 10% are more susceptible to nitrogen absorption under pressure, potentially resulting in bubbly cartridges. As such, it is crucial to implement some upstream processes to prepare unrefined extracts for filling. Such processes control the formulation constituents and reduce variability, resulting in high-quality cartridges with a premium taste and better customer experiences.   

Implementing Production Changes: Hydrocarbon Workflows

Since hydrocarbon producers usually have all the equipment for traditional wax, shatter, or diamonds-in-sauce extract production, they are well prepared to implement upstream changes. Yet some of our customers who produce hydrocarbon extract might not be familiar with the “liquid diamonds” approach to preparing extracts for vape cartridge filling machines, a multi-step solution with profound benefits. 

Producing Liquid Diamonds
  1. Winterize during extraction to reduce lipids present in the bulk extract. A bit of color remediation media (such as carbon or silica) aids in reducing unwanted compounds in the bulk extract. Processed in this way, THCa crystallizes and separates from the “sauce” (made of terpenes and other compounds). The resulting crystals can be greater than 95% pure (CC: Walter White). 
  2. Separate the crystals from the sauce with gravity or assistance from a centrifuge.  
  3. Decarboxylate and purge the crystals simultaneously under a hard vacuum, yielding a liquid purer than distillate refined with a wiped film apparatus
  4. Preserve terpenes by purging the sauce portion of hydrocarbons with low heat and vacuum. 
  5. Mix the liquid diamonds and sauce in known proportions (perhaps, 90/10 or 95/5). 

A quick note on vacuum purging: as with all vacuum purging processes, when purging hydrocarbons from the separated sauce and decarboxylating isolated diamonds, closely monitor heat and vacuum to prevent foaming and loss of product. 

My suggestion: when decarboxylating the diamonds, start at a lower temperature and vacuum pressure until carbon dioxide begins to bubble. Once you have bubbling, slowly increase the temperature and vacuum pressure; the bubbling will start to subside until it ceases entirely. When purging the sauce, use low vacuum pressure and low temperature until the hydrocarbons are below the testing limit; slow and steady wins this race

What is the filling process like?

When loaded into a Vape-Jet, this formulation behaves much more like a refined distillate and botanical terpene formulation. Why? Because when we separate the sauce and process the diamonds separately, we gain control of terpene content; we reduce batch and strain variability.  

Controlled Process vs Uncontrolled Process

The filling parameters on your Vape-Jet can be milder as well, resulting in a more flavorful and true-to-strain vape cartridge for connoisseur cannabis consumers. The leftover sauce can even be used to flavor more easily sourced cannabis distillates, generating options for a value-oriented SKU targeted toward more budget-conscious consumers.  

Distillate-with-sauce cartridges offer huge flavor improvements over botanically flavored distillate vape cartridges and are cheaper to produce than liquid-diamond-with-sauce vape carts. You can also use the leftover sauce in an MCT or coconut oil mixture to make strain-specific, precision-filled edible capsules with your Vape-Jet. 

Rosin Workflows

Unlike hydrocarbon producers, rosin producers may have to obtain equipment (like a precision-heated vacuum oven and a centrifuge) that is not common to their process. However, despite needing some equipment, rosin manufacturers can absolutely benefit from implementing a similar methodology for filling vape cartridges.  

Are there other differences between hydrocarbon and rosin workflows besides equipment needs?

Since there are no added solvents in rosin (only terpenes), the primary difference is the time needed to crystallize THCa. Due to strain variability, some rosin extracts will crash to crystals faster than others.

Okay, we have our equipment. Now what?

Generally speaking, you should heat bulk rosin under pressure (Rosin Jar Tech) until it begins to liquify and separate. Rather than whipping the extract to a batter-like consistency, process it to obtain larger crystals.  

As rosin producers know, rosin-based extracts contain more lipids than hydrocarbon extracts. This is why a centrifuge is especially useful for separating crystals from the sauce. Once separated, the process is similar to the hydrocarbon extraction we outlined above. To recap: fully decarboxylate THCa crystals under vacuum and mix the sauce into the liquid diamonds in known proportions. Since there are no hydrocarbon solvents in rosin, the sauce does not need to be heated or purged after separation. 

Now, you can start filling with precision and confidence on your Vape-Jet, knowing your customers will receive a reliable, quality product that will satisfy all cannabis connoisseurs.  

Start Filling

Coupled with our Vape-Jet, fully-automatic vape cartridge-filling machine, you can easily fill a variety of high-quality, great-tasting, and highly efficacious cannabis-derived vape cartridges, capsules, Dablicators, and precision-sauce-dosed diamond extracts.  

Sound good? I think so too, so why not contact us and optimize your vape cartridge production with the best filling machine in the game.  

Don’t forget to keep up-to-date by signing up for our monthly Re:Fill newsletter to get early access to company updates, product releases, and other exciting announcements. While you’re at it, follow us on Facebook, Instagram, and Linkedin for updates, friendship, and cats

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Laboratory Uncategorized

Laboratory Technique – Rotary Evaporator Optimization

This article explains the general process to achieve the maximum possible solvent recovery rate from any rotary evaporator.

Introduction

Rotary evaporation is a powerful technique for quickly removing solvent from a solution of cannabis or hemp extract. There are two distinct methods of operating a rotary evaporator: batch or continuous; choosing the correct one for the task is crucial. For the purposes typically required in the cannabis industry, i.e. winterization or color remediation of extracts, the necessary volume of solvent to be recovered invariably necessitates a continuous style of operation for rotary evaporators. Not only can solvent recovery rates be increased by 2-4x with this mode of operation, but overall throughput is increased as well since vacuum is maintained until the rotary flask (or solvent recovery flask) is ready to be emptied. 

Continuous Operation

In order to achieve the highest possible solvent recovery rate, several individual rates of the rotary evaporation process must be tuned to match or complement each other. The defining characteristic of continuous operation is the slow and constant addition of fresh solution into the rotary flask. Only as much solvent as can be evaporated and condensed should be added to the rotary flask per unit of time. In other words, the volume solvent dripping off the condenser should be equal to the volume of solvent containing solution dripping into the rotary flask.

Important Constants:

  1. Heat – the water bath provides heat to the evaporating surface of the rotary flask. Having enough hot water to cover a large area of the rotary flask is essential.
  2. Vacuum – the vacuum in the system can be thought of as essentially constant if the pump is of sufficient capacity. Having a large enough vacuum pump is vital.
  3. Cold – the condenser removes heat from the vapor and forces it to drip into the collection flask. Having a high cooling capacity is the most important factor.

These important constants are listed in order of increasing difficulty and cost to achieve. Heating water is a very easy and low cost part of the system, the vacuum pump is more specialized but relatively simple, while the refrigeration unit is the most complex and costly component. Having insufficient cooling capacity will dramatically decrease the maximum rate of solvent recovery possible from any rotary evaporation system.

The greater the difference in temperature (ΔT) between the hot (evaporation) and cold (condensation) sides of the system, the faster the solvent can be recovered.  

Ideally, the refrigeration unit of the rotary evaporator system will be large enough so that ΔT behaves as a constant during operation at maximum recovery; in reality, the refrigeration fluid will become hotter as evaporation and condensation begin, until it settles at its operating temperature. As the proportion of extract in the boiling flask increases and solvent decreases, the rate of evaporation will also decrease, resulting in a lower refrigerant temperature.

Important Rates:

Keeping the constants in mind, there are several factors which must be tuned in order to achieve maximum recovery. The ΔT for each system is unique and largely dependent upon the refrigeration unit, tuning the following rates to keep ΔT from changing is the essence of continuous operation of a rotary evaporator.

  1. Rotation – the rate at which solution is exposed to warm surface area to evaporate.
  2. Feed – the rate of addition of fresh solution into the boiling flask, limited by the rate of Evaporation. 
  3. Evaporation – how fast solvent transforms from liquid to gas, determined as a function of Rotation and Feed, in combination with Heat and Vacuum.
  4. Condensation – how fast solvent transforms from gas to liquid, determined as a function of Cooling and Vacuum.

In order to achieve maximum solvent recovery, the operator must tune Rotation and Feed rates such that Evaporation and Condensation rates become equal with the highest possible ΔT.

Example

  1. Attach a length of food-grade tubing to both sides of the Feed Valve.
    1. The rotary flask side of tubing should extend beyond the neck and slightly down the bulb, this reduces splash.
    2. The external side of tubing should be long enough to reach the bottom of the beaker or flask that contains your solution of extract and solvent (i.e. ethanol).
    3. Let your solution come to room temperature prior to solvent recovery, if possible. 
  2. Heat the water bath to at least 60C.
    1. Ensure there is enough water to come up almost to the level of the rotary flask neck, covering 30-40% of the flask when fully lowered.
  3. Turn on the refrigeration unit to its lowest possible setting, below 0C is ideal.
  4. Turn on the vacuum pump.
  5. Set flask rotation to about 100 revolutions per minute (RPM).
  6. Once the refrigerator and vacuum are as low as they can be, flask rotating, and with the external tubing in your solution containing beaker, slowly open the Feed Valve.
    1. Adjust feed valve to a very fine trickle, such that a band of extract forms immediately on the inner surface of the rotating flask.
    2. If a puddle forms or grows within the first few minutes, close the Feed Valve slightly.
    3. A puddle of extract rich solution will begin to form after several minutes, adjust RPM as needed to keep the puddle at the bottom of the flask.
    4. If the puddle is too rich in extract, the Feed Rate can be increased; if the puddle is too rich in solvent, decrease the Feed Rate.
  7. Monitor the refrigerator temperature throughout and adjust the Feed Valve accordingly, i.e. reduce Feed if temperature increases.
  8. Once the rotary flask approaches 30-50% full of extract rich solution, the Recovery Rate will decrease.
    1. Close Feed Valve to reduce chance of boil over, and continue rotary evaporation on the solution in the rotary flask until the desired level of completion.
  9. Remove and collect the extract from the rotary flask as normal with heat, gravity, and silicone scrapers.