Integrated Micro Lab Keeps Track Of Ammonia In The Blood

February 17, 2025 by Dan Maloney 6 Comments

We’ve all got our health-related crosses to bear, and even if you’re currently healthy, it’s only a matter of time before entropy catches up to you. For [Markus Bindhammer], it caught up to him in a big way: liver disease, specifically cirrhosis. The disease has a lot of consequences, none of which are pleasant, like abnormally high ammonia concentration in the blood. So naturally, [Markus] built an ammonia analyzer to monitor his blood.

Measuring the amount of ammonia in blood isn’t as straightforward as you think. Yes, there are a few cheap MEMS-based sensors, but they tend to be good only for qualitative measurements, and other solid-state sensors that are more quantitative tend to be pretty expensive since they’re mostly intended for industrial applications. [Marb]’s approach is based on the so-called Berthelot method, which uses a two-part reagent. In the presence of ammonia (or more precisely, ammonium ions), the reagent generates a dark blue-green species that absorbs light strongly at 660 nm. Measuring the absorbance at that wavelength gives an approximation of the ammonia concentration.

[Marb]’s implementation of this process uses a two-stage reactor. The first stage heats and stirs the sample in a glass tube using a simple cartridge heater from a 3D printer head and a stirrer made from a stepper motor with a magnetic arm. Heating the sample volatilizes any ammonia in it, which mixes with room air pumped into the chamber by a small compressor. The ammonia-laden air moves to the second chamber containing the Berthelot reagent, stirred by another stepper-powered stir plate. A glass frit diffuses the gas into the reagent, and a 660-nm laser and photodiode detect any color change. The video below shows the design and construction of the micro lab along with some test runs.

We wish [Markus] well in his journey, of course, especially since he’s been an active part of our community for years. His chemistry-related projects run the gamut from a homebrew gas chromatograph to chemical flip flops, with a lot more to boot.

Continue reading “Integrated Micro Lab Keeps Track Of Ammonia In The Blood” →

Improving Aluminium-Ion Batteries With Aluminium-Fluoride Salt

February 11, 2025 by Maya Posch 43 Comments

There are many rechargeable battery chemistries, each with their own advantages and disadvantages. Currently lithium-ion and similar (e.g. Li-Po) rule the roost due to their high energy density at least acceptable number of recharge cycles, but aluminium-ion (Al-ion) may become a more viable competitor after a recently published paper by Chinese researchers claims to have overcome some of the biggest hurdles. In the paper as published in ACS Central Science by [Ke Guo] et al. the use of solid-state electrolyte, a charge cycle endurance beating LiFePO₄ (LFP) and excellent recyclability are claimed.

It’s been known for a while that theoretically Al-ion batteries can be superior to Li-ion in terms of energy density, but the difficulty lies in the electrolyte, including its interface with the electrodes. The newly developed electrolyte (F-SSAF) uses aluminium-fluoride (AlF₃) to provide a reliable interface between the aluminium and carbon electrodes, with the prototype cell demonstrating 10,000 cycles with very little cell degradation. Here the AlF₃ provides the framework for the EMIC-AlCl₃ electrolyte. FEC (fluoroethylene carbonate) is introduced to resolve electrolyte-electrode interface issues.

A recovery of >80% of the AlF₃ during a recycling phase is also claimed, which for a prototype seems to be a good start. Of course, as the authors note in their conclusion, other frameworks than AlF₃ are still to be investigated, but this study brings Al-ion batteries a little bit closer to that ever-elusive step of commercialization and dislodging Li-ion.

Make Custom Shirts With A 3D Print, Just Add Bleach

February 10, 2025 by Donald Papp 38 Comments

Bleach is a handy way to mark fabrics, and it turns out that combining bleach with a 3D-printed design is an awfully quick-working and effective way to stamp a design onto a shirt.

Plain PLA stamp with bleach gives a slightly distressed look to this design.

While conceptually simple, the details make the difference. Spraying bleach onto the stamp surface helps get even coverage, and having the stamp facing “up” and lowering the shirt onto the stamp helps prevent bleach from running where it shouldn’t. Prompt application of hot air with a heat gun (followed by neutralizing or flushing any remaining bleach by rinsing in plenty of cold water) helps keep the edges of the design clean and sharp.

We wondered if combining techniques with some of the tips on how to 3D print ink stamps would yield even better results. For instance, we notice the PLA stamp (used to make the design in the images here) produces sharp lines with a slightly “eroded” look overall. This is very much like the result of inking with a stamp printed in PLA. With a stamp printed in flex filament, inking gives much more even results, and we suspect the same might be true for bleach.

Of course, don’t forget that it’s possible to 3D print directly onto fabric if you want your designs to be a little more controlled (and possibly in multiple colors). Or, try silkscreening. Who knew there were so many options for putting designs onto shirts? If you try it out and learn anything, let us know by sending in a tip!

Continue reading “Make Custom Shirts With A 3D Print, Just Add Bleach” →

Electroplating DIY PCB Vias At Home Without Chemical Baths

January 31, 2025 by Maya Posch 18 Comments

Although DIY PCB making has made great strides since the early days of chemical etching, there’s one fly in the ointment: vias. These connect individual layers of the board with a conductive tube, and are essential for dual-layer PCBs, never mind boards with a larger layer stack. The industry standard way of producing them is rather cumbersome and doesn’t scale well to a hobby or prototyping context. Might there be a better way? This is the question that [Levi Janssen] set out to answer with a new home PCB manufacturing project.

The goal here is to still electroplate the vias as with the commercial solution, just without having to use chemical baths. This way it should be suitable for an automated setup, with a tool head that performs the coating of the via with a high-resistance conductive ink before the electroplating step, all without submerging the entire PCB. After an initial experiment showed promising results, [Levi] committed to a full prototype.

This turned out to be a bridge too far, so the prototype was scaled down to a simpler machine. This is where the main issue with electroplating one via at a time became clear, as a standard 0.3 mm via takes easily 10 minutes to electroplate, even with an increase in voltage. At that point ordering a PCB from China becomes the faster option if you have enough vias in the design. Fortunately [Levi] figures he may have some solutions there, so we’ll have to wait and see what those are in the next installment. The video is below the break.

Continue reading “Electroplating DIY PCB Vias At Home Without Chemical Baths” →

DIY Strontium Aluminate Glows In The Dark

January 20, 2025 by Al Williams 8 Comments

[Maurycyz] points out right up front: several of the reagents used are very corrosive and can produce toxic gasses. We weren’t sure if they were trying to dissuade us not to replicate it or encourage us to do so. The project in question is making strontium aluminate which, by the way, glows in the dark.

The material grows strongly for hours and, despite the dangers of making it, it doesn’t require anything very exotic. As [Maurycyz] points out, oxygen and aluminum are everywhere. Strontium sounds uncommon, but apparently, it is used in ceramics.

For the chemists among us, there’s an explanation of how to make it by decomposing soluble nitrate salts. For the rest of us, the steps are to make aluminum hydroxide using potassium alum, a food preservative, and sodium hydroxide. Then, it is mixed with nitric acid, strontium carbonate, europium, and dysprosium. Those last elements determine the color of the glow.

A drying step removes the acid, followed by dissolving with urea and water. The heat of the reaction wasn’t enough to form the final product, but it took time with an oxy-propane torch to form blobs of strontium aluminate. The product may not have been pure, because it didn’t glow for hours like commercial preparations. But it did manage to glow for a few minutes after light exposure.

We try to limit our chemistry to less toxic substances, although ferric chloride can make a mess. You could probably track down the impurities with a gas chromatograph. What we really want is a glow-in-the-dark car antenna.

Simple Fluorometer Makes Nucleic Acid Detection Cheap And Easy

December 18, 2024 by Dan Maloney 9 Comments

Back in the bad old days, dealing with DNA and RNA in a lab setting was often fraught with peril. Detection technologies were limited to radioisotopes and hideous chemicals like ethidium bromide, a cherry-red solution that was a fast track to cancer if accidentally ingested. It took time, patience, and plenty of training to use them, and even then, mistakes were commonplace.

Luckily, things have progressed a lot since then, and fluorescence detection of nucleic acids has become much more common. The trouble is that the instruments needed to quantify these signals are priced out of the range of those who could benefit most from them. That’s why [Will Anderson] et al. came up with DIYNAFLUOR, an open-source nucleic acid fluorometer that can be built on a budget. The chemical principles behind fluorometry are simple — certain fluorescent dyes have the property of emitting much more light when they are bound to DNA or RNA than when they’re unbound, and that light can be measured easily. DIYNAFLUOR uses 3D-printed parts to hold a sample tube in an optical chamber that has a UV LED for excitation of the sample and a TLS2591 digital light sensor to read the emitted light. Optical bandpass filters clean up the excitation and emission spectra, and an Arduino runs the show.

The DIYNAFLUOR team put a lot of effort into making sure their instrument can get into as many hands as possible. First is the low BOM cost of around $40, which alone will open a lot of opportunities. They’ve also concentrated on making assembly as easy as possible, with a solder-optional design and printed parts that assemble with simple fasteners. The obvious target demographic for DIYNAFLUOR is STEM students, but the group also wants to see this used in austere settings such as field research and environmental monitoring. There’s a preprint available that shows results with commercial fluorescence nucleic acid detection kits, as well as detailing homebrew reagents that can be made in even modestly equipped labs.

Ore To Iron In A Few Seconds: New Chinese Process Will Revolutionise Smelting

December 12, 2024 by Jenny List 93 Comments

The process of ironmaking has relied for centuries on iron ore, an impure form of iron oxide, slowly being reduced to iron by carbon monoxide in a furnace. Whether that furnace is the charcoal fire of an Iron Age craftsman or a modern blast furnace, the fundamental process remains the same, even if the technology around it has been refined. Now details are emerging of a new take on iron smelting from China, which turns what has always been a slow and intensive process into one that only takes a few seconds. So-called flash ironmaking relies on the injection of a fine iron ore powder into a superheated furnace, with the reduction happening explosively and delivering a constant stream of molten iron.

Frustratingly there is little detail on how it works, with the primary source for the news coverage being a paywalled South China Morning Post article. The journal article alluded to has proved frustratingly difficult to find online, leaving us with a few questions as to how it all works. Is the reducing agent still carbon monoxide, for example, or do they use another one such as hydrogen? The interesting part from an economic perspective is that it’s said to work on lower-grade ores, opening up the prospect for the Chinese steelmakers relying less on imports. There’s no work though on how the process would deal with the inevitable slag such ore would create.

If any readers have journal access we’d be interested in some insight in the comments, and we’re sure this story will deliver fresh information over time. Having been part of building a blast furnace of our own in the past, it’s something we find interesting